How to fix misaligned assignment statements in the source code?

Hello All,

I'm not a C/C++ programmer, but I'm familiar with this programm language.

The thing is that I'm trying to compile and run DDS (Darwin Streaming Server) on "Gentoo on Sparc" architecture.

Although I've managed to compile DSS under my arch. I'm constatntly get "Bus error" while trying to connect to DSS with QT player.

I've read that:

"The "bus error" signal usually means a data access was not properly aligned. It is always due to an error in the program.

One major cause is accessing data via a pointer of a different type that has different alignment requirements. Example:

Code:

---

short s[2]; // 2-byte alignment

int* p = (int*)s; // pretend the 2 shorts are one int int i = *p; // bus error is likely

---

On SPARC, an int must be aligned on a 4-byte boundary, but a short only needs 2-byte alignment. The attempted load fails with a bus error if array s was not 4-byte aligned.

Here is the example of resolution for this kind of problem on another project (a snap from the .diff):

Code:

---


@@ -499,8 +499,11 @@
        conn->request_len -= req->len;
        if (conn->request_len == 0)
            break;
-
+#if defined (__i386__)
 req = (void *) req + req->len;
+#else
+memmove(&conn->request, (void *)req + req->len, conn->request_len);
+#endif
    }
 
    if (conn->request_len > 0 && req != &conn->request)

---

So I thought there may be some way to overcome these alignment requirements by may be replacing (with some search and replace func.) int and short definitions with the proper ones?

As I've said I'm not a C/C++ programmer so I hope you could give me some good advices to resolve this problem :)

The short answer is not to do tricks like casting a pointer to short into a pointer to int, as anything you do with that pointer to int subsequently yields undefined behaviour. If you want an int, declare it as an int. Or, to put it another way, find a way to write your program so you can make it compile without using a typecast (which is simply an instruction to the compiler not to complain when you do something potentially invalid).

The most common basic reason for wanting to interpret an array of shorts as an int is that your program makes assumptions about relative sizes of types (eg in your case, you are assuming an int is twice the size of a short --- which is not true for all compilers). There are all sorts of reasons why you may wish to make that assumption (eg saving data in a binary format, which means both the program reading the file and the program writing the file must agree on precise layout of bits in characters, shorts, floats, data structures, etc) and eliminating such assumptions often requires basic design changes (eg defining a protocol and enforcing it in a PORTABLE manner).

Incidentally, bus errors can result from other invalid operations on pointers (not just from issues with alignment). While the most common behaviour from invalid pointer operations (eg dereferencing a NULL, falling off the end of an array) is a core dump, a bus error is another possible result.

> Here is the example of resolution for this kind of problem on another project
Here's an example of the blind leading the stupid more like.
That's just ugly hackery, not a solution.

> +#if defined (__i386__)
> req = (void *) req + req->len;
Two problems here
1. Unaligned accesses are not unique to this architecture. Even where it is allowed, there may be a performance penalty (up to and including an exception trap to the OS).
2. Arithmetic on void* is undefined - void has no size, therefore how can you add anything to it?
Eg.
foo.c:4: warning: pointer of type ‘void *’ used in arithmetic

> +#else
> +memmove(&conn->request, (void *)req + req->len, conn->request_len);
1. But now the input data has been modified, which means something else later on in the code could be in for a big surprise.
2. And the afore mentioned arithmetic on void*

On the whole, fairly typical of the "works for me and my compiler" brigade.

The best answer would have been to declare a new variable of the correct type, then memcpy() from the source to that variable. It always works and no messy conditional compilations, and no unexpected modifications of source data.

> some good advices to resolve this problem
Yes, fill out bug reports on the home site of that open source project pointing out the lack of portability of the code.
Compile the code with debug symbols, run the code in a debugger and submit stack traces would probably be a good start.

Oh yeah, and echo everything grumpy said as well.

Thank you all for the answers,

I've posted several questions on this problem to the developer list of DSS, but got no reply at all.
Tried to find any active developer for this project but uselessly :(

I've maked some changes to the source to make it recognize sparc64 arch., compiled but as I've said there is a "bus error" preventing me to use the programm.

I've tried to debug the programm, using instructions I found on some 2001 year post to the list,
with the below instructions:

Code:

---

root# ./gdbdar (or gdb ./DarwinStreamingServer -x gdb_script)

Then, run the server like this:

    (at the GDB prompt)
    r -d -S 5

(which means -debug, stay attached to the session, and -S 5 means print status every 5 seconds)

Now, connect your QT 5 client and see if the server crashes.  If so, then get a backtrace
send it to use via the email to the Darwin Streaming Developers mailing list.

  (at the GDB prompt, after the crash occurs)
  bt

---

I had to kill gdb process, cause it won't end:

Code:

---

# ./gdbdar
GNU gdb 6.4
Copyright 2005 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "sparc-unknown-linux-gnu"...Using host libthread_db l            ibrary "/lib/libthread_db.so.1".

(gdb) r -d -S 5
Starting program: /opt/dss8/DarwinStreamingSrvr5.5-Source/DarwinStreamingServer            -d -S 5
[Thread debugging using libthread_db enabled]
[New Thread 16384 (LWP 20477)]

---

Below are my compilation warnings:

Code:

---

Below there are my compilation warnings (May be it willl help in some way to recognize the problem):

StrPtrLen.cpp: In member function `Bool16 StrPtrLen::NumEqualIgnoreCase(const char*, UInt32) const':
StrPtrLen.cpp:143: warning: array subscript has type `char'
StrPtrLen.cpp:143: warning: array subscript has type `char'
StrPtrLen.cpp: In member function `Bool16 StrPtrLen::EqualIgnoreCase(const char*, UInt32) const':
StrPtrLen.cpp:156: warning: array subscript has type `char'
StrPtrLen.cpp:156: warning: array subscript has type `char'
StrPtrLen.cpp: In member function `void StrPtrLen::PrintStr()':
StrPtrLen.cpp:306: warning: array subscript has type `char'
StrPtrLen.cpp: In member function `void StrPtrLen::PrintStrEOL(char*, char*)':
StrPtrLen.cpp :336: warning: array subscript has type `char'
UDPSocketPool.cpp: In member function `UDPSocketPair* UDPSocketPool::CreateUDPSocketPair(UInt32, UInt16)':
UDPSocketPool.cpp:112: warning: comparison is always true due to limited range of data type In file included from SDPUtils.cpp:26:
SDPUtils.h: In member function `Bool16 SDPContainer::HasLineType(char)':
SDPUtils.h:92: warning: array subscript has type `char'
SDPUtils.cpp: In member function `void SDPContainer::Parse()':
SDPUtils.cpp:137: warning: array subscript has type `char'
ar: creating libCommonUtilitiesLib.a
ar: creating libQTFileLib.a
ar: creating libQTFileExternalLib.a
Server.tproj/QTSSDataConverter.cpp: In static member function `static QTSS_Error QTSSDataConverter::ConvertCHexStringToBytes(char*, void*, UInt32*)':
Server.tproj/QTSSDataConverter.cpp:270: warning: array subscript has type `char'
Server.tproj/QTSSDataConverter.cpp:272: warning: array subscript has type `char'
In file included from APICommonCode/SDPSourceInfo.cpp:40:
CommonUtilitiesLib/SDPUtils.h: In member function `Bool16 SDPContainer::HasLineType(char)':
CommonUtilitiesLib/SDPUtils.h:92: warning: array subscript has type `char'
In file included from APIModules/QTSSFileModule/QTSSFileModule.cpp:48:
CommonUtilitiesLib/SDPUtils.h: In member function `Bool16 SDPContainer::HasLineType(char)':
CommonUtilitiesLib/SDPUtils.h:92: warning: array subscript has type `char'
In file included from APIModules/QTSSReflectorModule/QTSSReflectorModule.cpp:59:
CommonUtilitiesLib/SDPUtils.h: In member function `Bool16 SDPContainer::HasLineType(char)':
CommonUtilitiesLib/SDPUtils.h:92: warning: array subscript has type `char'
APIModules/QTSSReflectorModule/QTSSReflectorModule.cpp: In function `void DoAnnounceAddRequiredSDPLines(QTSS_StandardRTSP_Params*, ResizeableStringFormatter*, char*)':
APIModules/QTSSReflectorModule/QTSSReflectorModule.cpp:847: warning: array subscript has type `char'
In file included from APIModules/QTSSReflectorModule/RTSPSourceInfo.cpp:42:
CommonUtilitiesLib/SDPUtils.h: In member function `Bool16 SDPContainer::HasLineType(char)':
CommonUtilitiesLib/SDPUtils.h:92: warning: array subscript has type `char'
/usr/lib/gcc/sparc-unknown-linux-gnu/3.4.6/../../../../sparc-unknown-linux-gnu/bin/ld: warning: creating a DT_TEXTREL in object.
/usr/lib/gcc/sparc-unknown-linux-gnu/3.4.6/../../../../sparc-unknown-linux-gnu/bin/ld: warning: creating a DT_TEXTREL in object.
/usr/lib/gcc/sparc-unknown-linux-gnu/3.4.6/../../../../sparc-unknown-linux-gnu/bin/ld: warning: creating a DT_TEXTREL in object.
/usr/lib/gcc/sparc-unknown-linux-gnu/3.4.6/../../../../sparc-unknown-linux-gnu/bin/ld: warning: creating a DT_TEXTREL in object.
/usr/lib/gcc/sparc-unknown-linux-gnu/3.4.6/../../../../sparc-unknown-linux-gnu/bin/ld: warning: creating a DT_TEXTREL in object.
proxy.c: In function `sig_catcher':
proxy.c:177: warning: implicit declaration of function `sigignore'
QTSSPasswd.cpp:422: warning: 'char* SetTempPath(char*, int, char*, int, char)' defined but not used In file included from playlist_SDPGen.cpp:31:
../CommonUtilitiesLib/SDPUtils.h: In member function `Bool16 SDPContainer::HasLineType(char)':
../CommonUtilitiesLib/SDPUtils.h:92: warning: array subscript has type `char'
In file included from BroadcasterSession.cpp:38:
../CommonUtilitiesLib/SDPUtils.h: In member function `Bool16 SDPContainer::HasLineType(char)':
../CommonUtilitiesLib/SDPUtils.h:92: warning: array subscript has type `char'

---

It seems that I'm on my own with this problem, thats why I got here to this programmers forum.

I'll give you any info on the source or compilation process for this programm if would kindly help me to solve this problem.

You should pay attention to some of those warnings, like these:

Code:

---

StrPtrLen.cpp:143: warning: array subscript has type `char'
UDPSocketPool.cpp:112: warning: comparison is always true due to limited range of data type In file included from SDPUtils.cpp:26:

---

It looks like you're using too many chars, in ways like

Code:

---

char c;
if(c < 1000) array[c];

---

> thats why I got here to this programmers forum
But most forums like this are for helping newbies learn the language and fix problems with their own code.

"I downloaded foo, but it doesn't work, please fix foo for me" posts like yours are considerably more time consuming to deal with. We can give general advice on what to look for, or what to try next but the bulk of the effort is going to have to be yours.

> I'm not a C/C++ programmer, but I'm familiar with this programm language.
Familiar enough to make changes to the code ?

Here are a few steps you can take
1. If you know about cvs or sccs or rcs, then I would suggest you start using it by putting a clean copy of this project into it. Keeping track of changes is going to be important.
At the very least, have directories which contains all the code "as downloaded" and then all the code "as edited".

2. Fix warnings as you find them - all those "char as subscript" are simply horrible in something which alludes to being something to do with strings.

3. The next step would be to compile the code with this flag, and look closely at anything it flags up

Code:

---

`-Wcast-align'
    Warn whenever a pointer is cast such that the required alignment
    of the target is increased.  For example, warn if a `char *' is
    cast to an `int *' on machines where integers can only be accessed
    at two- or four-byte boundaries.

---

Anything doing this is capable of (though not guaranteed to) drawing a bus error.

> proxy.c: In function `sig_catcher':
Check whether anything is catching / ignoring SIGBUS, or any other fatal signals. Doing so may interfere with your ability to debug the program. Maybe fine when the server is in use, but you want to make it useful for debugging.
Likewise, are there any calls to daemon() or fork() in the code. You could be debugging the wrong process if you're not careful.

I found this link on DT_TEXTREL
http://www.codecomments.com/archive2...-6-517685.html
Try pasting error messages into google in the first instance if you're stuck.

Hello,

Thanks for all the responses here.

The -fPIC compiler flag indeed removes DT_TEXTREL... warnings :)

I've started with adding `-Wcast-align' to the compiler options,
and got a lot of these warnings (it's just a little snap):

Code:

---

APIModules/QTSSReflectorModule/ReflectorStream.h: In member function `UInt32 ReflectorPacket::GetSSRC(Bool16)':
APIModules/QTSSReflectorModule/ReflectorStream.h:120: warning: cast from `char*' to `UInt32*' increases required alignment of target type
APIModules/QTSSReflectorModule/ReflectorStream.h: In member function `UInt32 ReflectorPacket::GetPacketRTPTime()':
APIModules/QTSSReflectorModule/ReflectorStream.h:139: warning: cast from `char*' to `UInt32*' increases required alignment of target type
APIModules/QTSSReflectorModule/ReflectorStream.h:145: warning: cast from `char*' to `UInt32*' increases required alignment of target type
APIModules/QTSSReflectorModule/ReflectorStream.h: In member function `UInt16 ReflectorPacket::GetPacketRTPSeqNum()':
APIModules/QTSSReflectorModule/ReflectorStream.h:157: warning: cast from `char*' to `UInt16*' increases required alignment of target type
APIModules/QTSSReflectorModule/ReflectorStream.h: In member function `SInt64 ReflectorPacket::GetPacketNTPTime()':
APIModules/QTSSReflectorModule/ReflectorStream.h:168: warning: cast from `char*' to `UInt32*' increases required alignment of target type
In file included from APIModules/QTSSReflectorModule/RTSPSourceInfo.cpp:42:
CommonUtilitiesLib/SDPUtils.h: In member function `Bool16 SDPContainer::HasLineType(char)':
CommonUtilitiesLib/SDPUtils.h:92: warning: array subscript has type `char'
In file included from APIModules/QTSSReflectorModule/ReflectorStream.h:55,
                from APIModules/QTSSReflectorModule/ReflectorSession.h:45,
                from APIModules/QTSSReflectorModule/RelaySession.h:35,
                from APIModules/QTSSReflectorModule/RelayOutput.h:37,
                from APIModules/QTSSReflectorModule/RelayOutput.cpp:34:
RTCPUtilitiesLib/RTCPSRPacket.h: In member function `void RTCPSRPacket::SetSSRC(UInt32)':
RTCPUtilitiesLib/RTCPSRPacket.h:112: warning: cast from `char (*)[132]' to `UInt32*' increases required alignment of target type
RTCPUtilitiesLib/RTCPSRPacket.h:115: warning: cast from `char (*)[132]' to `UInt32*' increases required alignment of target type
RTCPUtilitiesLib/RTCPSRPacket.h:119: warning: cast from `char (*)[132]' to `UInt32*' increases required alignment of target type
RTCPUtilitiesLib/RTCPSRPacket.h:123: warning: cast from `char (*)[132]' to `UInt32*' increases required alignment of target type
RTCPUtilitiesLib/RTCPSRPacket.h: In member function `void RTCPSRPacket::SetClientSSRC(UInt32)':
RTCPUtilitiesLib/RTCPSRPacket.h:130: warning: cast from `char (*)[132]' to `UInt32*' increases required alignment of target type
RTCPUtilitiesLib/RTCPSRPacket.h: In member function `void RTCPSRPacket::SetNTPTimestamp(SInt64)':
RTCPUtilitiesLib/RTCPSRPacket.h:136: warning: cast from `char (*)[132]' to `SInt64*' increases required alignment of target type
RTCPUtilitiesLib/RTCPSRPacket.h: In member function `void RTCPSRPacket::SetRTPTimestamp(UInt32)':
RTCPUtilitiesLib/RTCPSRPacket.h:145: warning: cast from `char (*)[132]' to `UInt32*' increases required alignment of target type
RTCPUtilitiesLib/RTCPSRPacket.h: In member function `void RTCPSRPacket::SetPacketCount(UInt32)':
RTCPUtilitiesLib/RTCPSRPacket.h:150: warning: cast from `char (*)[132]' to `UInt32*' increases required alignment of target type
RTCPUtilitiesLib/RTCPSRPacket.h: In member function `void RTCPSRPacket::SetByteCount(UInt32)':
RTCPUtilitiesLib/RTCPSRPacket.h:155: warning: cast from `char (*)[132]' to `UInt32*' increases required alignment of target type
RTCPUtilitiesLib/RTCPSRPacket.h: In member function `void RTCPSRPacket::SetAckTimeout(UInt32)':
RTCPUtilitiesLib/RTCPSRPacket.h:160: warning: cast from `char (*)[132]' to `UInt32*' increases required alignment of target type
In file included from APIModules/QTSSReflectorModule/ReflectorSession.h:45,
                from APIModules/QTSSReflectorModule/RelaySession.h:35,
                from APIModules/QTSSReflectorModule/RelayOutput.h:37,
                from APIModules/QTSSReflectorModule/RelayOutput.cpp:34:
APIModules/QTSSReflectorModule/ReflectorStream.h: In member function `UInt32 ReflectorPacket::GetSSRC(Bool16)':
APIModules/QTSSReflectorModule/ReflectorStream.h:120: warning: cast from `char*' to `UInt32*' increases required alignment of target type
APIModules/QTSSReflectorModule/ReflectorStream.h: In member function `UInt32 ReflectorPacket::GetPacketRTPTime()':
APIModules/QTSSReflectorModule/ReflectorStream.h:139: warning: cast from `char*' to `UInt32*' increases required alignment of target type
APIModules/QTSSReflectorModule/ReflectorStream.h:145: warning: cast from `char*' to `UInt32*' increases required alignment of target type
APIModules/QTSSReflectorModule/ReflectorStream.h: In member function `UInt16 ReflectorPacket::GetPacketRTPSeqNum()':
APIModules/QTSSReflectorModule/ReflectorStream.h:157: warning: cast from `char*' to `UInt16*' increases required alignment of target type
APIModules/QTSSReflectorModule/ReflectorStream.h: In member function `SInt64 ReflectorPacket::GetPacketNTPTime()':
APIModules/QTSSReflectorModule/ReflectorStream.h:168: warning: cast from `char*' to `UInt32*' increases required alignment of target type
In file included from APIModules/QTSSReflectorModule/ReflectorStream.h:55,
                from APIModules/QTSSReflectorModule/ReflectorSession.h:45,
                from APIModules/QTSSReflectorModule/RTPSessionOutput.h:40,
                from APIModules/QTSSReflectorModule/RTPSessionOutput.cpp:34:
RTCPUtilitiesLib/RTCPSRPacket.h: In member function `void RTCPSRPacket::SetSSRC(UInt32)':
RTCPUtilitiesLib/RTCPSRPacket.h:112: warning: cast from `char (*)[132]' to `UInt32*' increases required alignment of target type
RTCPUtilitiesLib/RTCPSRPacket.h:115: warning: cast from `char (*)[132]' to `UInt32*' increases required alignment of target type
RTCPUtilitiesLib/RTCPSRPacket.h:119: warning: cast from `char (*)[132]' to `UInt32*' increases required alignment of target type
RTCPUtilitiesLib/RTCPSRPacket.h:123: warning: cast from `char (*)[132]' to `UInt32*' increases required alignment of target type
RTCPUtilitiesLib/RTCPSRPacket.h: In member function `void RTCPSRPacket::SetClientSSRC(UInt32)':
RTCPUtilitiesLib/RTCPSRPacket.h:130: warning: cast from `char (*)[132]' to `UInt32*' increases required alignment of target type
RTCPUtilitiesLib/RTCPSRPacket.h: In member function `void RTCPSRPacket::SetNTPTimestamp(SInt64)':
RTCPUtilitiesLib/RTCPSRPacket.h:136: warning: cast from `char (*)[132]' to `SInt64*' increases required alignment of target type
RTCPUtilitiesLib/RTCPSRPacket.h: In member function `void RTCPSRPacket::SetRTPTimestamp(UInt32)':
RTCPUtilitiesLib/RTCPSRPacket.h:145: warning: cast from `char (*)[132]' to `UInt32*' increases required alignment of target type
RTCPUtilitiesLib/RTCPSRPacket.h: In member function `void RTCPSRPacket::SetPacketCount(UInt32)':
RTCPUtilitiesLib/RTCPSRPacket.h:150: warning: cast from `char (*)[132]' to `UInt32*' increases required alignment of target type
RTCPUtilitiesLib/RTCPSRPacket.h: In member function `void RTCPSRPacket::SetByteCount(UInt32)':
RTCPUtilitiesLib/RTCPSRPacket.h:155: warning: cast from `char (*)[132]' to `UInt32*' increases required alignment of target type
RTCPUtilitiesLib/RTCPSRPacket.h: In member function `void RTCPSRPacket::SetAckTimeout(UInt32)':
RTCPUtilitiesLib/RTCPSRPacket.h:160: warning: cast from `char (*)[132]' to `UInt32*' increases required alignment of target type
In file included from APIModules/QTSSReflectorModule/ReflectorSession.h:45,
                from APIModules/QTSSReflectorModule/RTPSessionOutput.h:40,
                from APIModules/QTSSReflectorModule/RTPSessionOutput.cpp:34:
APIModules/QTSSReflectorModule/ReflectorStream.h: In member function `UInt32 ReflectorPacket::GetSSRC(Bool16)':
APIModules/QTSSReflectorModule/ReflectorStream.h:120: warning: cast from `char*' to `UInt32*' increases required alignment of target type
APIModules/QTSSReflectorModule/ReflectorStream.h: In member function `UInt32 ReflectorPacket::GetPacketRTPTime()':
APIModules/QTSSReflectorModule/ReflectorStream.h:139: warning: cast from `char*' to `UInt32*' increases required alignment of target type
APIModules/QTSSReflectorModule/ReflectorStream.h:145: warning: cast from `char*' to `UInt32*' increases required alignment of target type
APIModules/QTSSReflectorModule/ReflectorStream.h: In member function `UInt16 ReflectorPacket::GetPacketRTPSeqNum()':
APIModules/QTSSReflectorModule/ReflectorStream.h:157: warning: cast from `char*' to `UInt16*' increases required alignment of target type
APIModules/QTSSReflectorModule/ReflectorStream.h: In member function `SInt64 ReflectorPacket::GetPacketNTPTime()':
APIModules/QTSSReflectorModule/ReflectorStream.h:168: warning: cast from `char*' to `UInt32*' increases required alignment of target type
APIModules/QTSSReflectorModule/RTPSessionOutput.cpp: In member function `QTSS_Error RTPSessionOutput::RewriteRTCP(void**, StrPtrLen*, SInt64*, UInt32, SInt64*, SInt64*, UInt64*, SInt64*)':
APIModules/QTSSReflectorModule/RTPSessionOutput.cpp:399: warning: cast from `char*' to `UInt32*' increases required alignment of target type
APIModules/QTSSReflectorModule/RTPSessionOutput.cpp:401: warning: cast from `UInt32*' to `SInt64*' increases required alignment of target type
APIModules/QTSSReflectorModule/RTPSessionOutput.cpp: In member function `UInt16 RTPSessionOutput::GetPacketSeqNumber(StrPtrLen*)':
APIModules/QTSSReflectorModule/RTPSessionOutput.cpp:622: warning: cast from `char*' to `UInt16*' increases required alignment of target type
APIModules/QTSSReflectorModule/RTPSessionOutput.cpp: In member function `void RTPSessionOutput::SetPacketSeqNumber(StrPtrLen*, UInt16)':
APIModules/QTSSReflectorModule/RTPSessionOutput.cpp:632: warning: cast from `char*' to `UInt16*' increases required alignment of target type
APIModules/QTSSWebStatsModule/QTSSWebStatsModule.cpp: In function `void SendStats(void*, UInt32, Bool16, StrPtrLen*)':
APIModules/QTSSWebStatsModule/QTSSWebStatsModule.cpp:650: warning: cast from `char*' to `UInt16*' increases required alignment of target type
APIModules/QTSSAdminModule/AdminElementNode.cpp: In member function `void ElementNode::SetElementDataPtr(SInt32, char*, Bool16)':
APIModules/QTSSAdminModule/AdminElementNode.cpp:639: warning: cast from `char*' to `ElementNode*' increases required alignment of target type
APIModules/QTSSAdminModule/AdminElementNode.cpp: In member function `virtual void ElementNode::SetUpSingleNode(QueryURI*, StrPtrLen*, StrPtrLen*, SInt32, QTSS_Initialize_Params*)':
APIModules/QTSSAdminModule/AdminElementNode.cpp:714: warning: cast from `char*' to `ElementNode*' increases required alignment of target type
APIModules/QTSSAdminModule/AdminElementNode.cpp: In member function `void ElementNode::RespondWithSingleElement(void*, QueryURI*, StrPtrLen*)':
APIModules/QTSSAdminModule/AdminElementNode.cpp:1844: warning: cast from `char*' to `ElementNode*' increases required alignment of target type
APIModules/QTSSAdminModule/AdminElementNode.cpp: In member function `void ElementNode::RespondWithAllElements(void*, QueryURI*, StrPtrLen*)':
APIModules/QTSSAdminModule/AdminElementNode.cpp:1942: warning: cast from `char*' to `ElementNode*' increases required alignment of target type
APIModules/QTSSAdminModule/AdminElementNode.cpp: In member function `void ElementNode::RespondWithAllNodes(void*, QueryURI*, StrPtrLen*)':
APIModules/QTSSAdminModule/AdminElementNode.cpp:1990: warning: cast from `char*' to `ElementNode*' increases required alignment of target type
APIModules/QTSSMP3StreamingModule/QTSSMP3StreamingModule.cpp: In function `QTSS_Error SessionClosing(QTSS_RTSPSession_Params*)':
APIModules/QTSSMP3StreamingModule/QTSSMP3StreamingModule.cpp:1927: warning: cast from `MP3Session*' to `MP3ClientSession*' increases required alignment of target type
APIModules/QTSSMP3StreamingModule/QTSSMP3StreamingModule.cpp: In function `QTSS_Error ReEnterFilterRequest(QTSS_Filter_Params*, MP3Session*)':
APIModules/QTSSMP3StreamingModule/QTSSMP3StreamingModule.cpp:2704: warning: cast from `MP3Session*' to `MP3ClientSession*' increases required alignment of target type
APIModules/QTSSRTPFileModule/RTPFileSession.cpp: In member function `RTPFileSession::ErrorCode RTPFileSession::Seek(Float64)':
APIModules/QTSSRTPFileModule/RTPFileSession.cpp:216: warning: cast from `UInt8*' to `RTPFilePacket*' increases required alignment of target type
APIModules/QTSSRTPFileModule/RTPFileSession.cpp:228: warning: cast from `UInt8*' to `UInt16*' increases required alignment of target type
APIModules/QTSSRTPFileModule/RTPFileSession.cpp:229: warning: cast from `UInt8*' to `UInt32*' increases required alignment of target type
APIModules/QTSSRTPFileModule/RTPFileSession.cpp: In member function `Float64 RTPFileSession::GetNextPacket(UInt8**, UInt32*, void**)':
APIModules/QTSSRTPFileModule/RTPFileSession.cpp:309: warning: cast from `UInt8*' to `RTPFilePacket*' increases required alignment of target type
APIModules/QTSSRTPFileModule/RTPFileSession.cpp:347: warning: cast from `UInt8*' to `UInt32*' increases required alignment of target type

---

Doing a little research on the net I've found
"QuickTime Streaming Server Modules - Programming Guide"
with -

Code:

---

Naming Conventions:
The QTSS programming interface uses a naming convention for the data types that it defines. The
convention is to use the size of the data type in the name. Here are the data types that the QTSS
programming interface uses:
■ Bool16— A 16-bit Boolean value
■ SInt64— A signed 64-bit integer value
■ SInt32— A signed 32-bit integer value
■ UInt16— An unsigned 16-bit integer value
■ UInt32— An unsigned 32-bit integer value
Parameters for callback functions defined by the QTSS programming interface follow these naming
conventions:
■ Input parameters begin with in.
■ Output parameters begin with out.
■ Parameters that are used for both input and output begin with io.

Data Types:
Data types can be any server-allowed text value. New data types can be defined and returned by the
server, so data types are not limited to the basic set listed here:
UInt8 SInt16 UInt64 Float64 char
SInt8 UInt32 SInt64 Bool8 QTSS_Object
UInt16 SInt32 Float32 Bool16 void_pointer
Values of type QTSS_Object, pointers, and unknown data types always converted to a host-ordered
string of hexadecimal values. Here is an example of a hexadecimal value result:
unknown_pointer=halogen; type=void_pointer

---

May be one possible solution is to replace all UInt16 to UInt32?

But what to do in the case of "cast from `char*' to `UInt16*'" or `char*' to `UInt32*' or `char*' to `short unsigned int*'?

Code:

---

playlist_elements.cpp: In member function `SInt16 RTpPacket::GetHeaderInfo(UInt32*, UInt16*, UInt32*, unsigned char*)':
playlist_elements.cpp:825: warning: cast from `char*' to `UInt16*' increases required alignment of target type
playlist_elements.cpp:826: warning: cast from `char*' to `UInt32*' increases required alignment of target type
playlist_elements.cpp: In member function `SInt16 RTpPacket::SetHeaderInfo(UInt32, UInt16, UInt32, unsigned char)':
playlist_elements.cpp:847: warning: cast from `char*' to `UInt16*' increases required alignment of target type
playlist_elements.cpp:848: warning: cast from `char*' to `UInt32*' increases required alignment of target type

---

Any Suggestions?

Wow, all that code in header files is sure bloating your executables.

> But what to do in the case of "cast from `char*' to `UInt16*'" or `char*' to `UInt32*' or `char*' to `short unsigned int*'?
I explained already - declare a variable of the right type, then do a memcpy()

Hi,

Sorry, but I need some practical example (As I've said I'm not as good with C/C++ as I would like).

Lets say I got these warnings:

Code:

---

SocketUtils.cpp: In static member function `static void SocketUtils::Initialize(Bool16)':
SocketUtils.cpp:375: warning: cast from `char*' to `ifreq*' increases required alignment of target type
SocketUtils.cpp:422: warning: cast from `UInt8*' to `SocketUtils::IPAddrInfo*' increases required alignment of target type
SocketUtils.cpp:472: warning: cast from `char*' to `ifreq*' increases required alignment of target type
SocketUtils.cpp:482: warning: cast from `sockaddr*' to `sockaddr_in*' increases required alignment of target type

---

And SocketUtils.cpp looks like this:

Code:

---


    26    File:      SocketUtils.cpp
    27
    28    Contains:  Implements utility functions defined in SocketUtils.h
    29
    30
    31
    32
    33 */
    34
    35 #include <string.h>
    36
    37 #ifndef __Win32__
    38 #include <sys/types.h>
    39 #include <sys/socket.h>
    40 #include <netinet/in.h>
    41 #include <arpa/inet.h>
    42 #include <netdb.h>
    43 #include <sys/ioctl.h>
    44
    45 #if __FreeBSD__
    46 #include <ifaddrs.h>
    47 #endif
    48 #include <unistd.h>
    49 #include <sys/utsname.h>
    50
    51 #if __solaris__
    52 #include <sys/sockio.h>
    53 #endif
    54 #endif
    55
    56 #include "SocketUtils.h"
    57
    58 #ifdef SIOCGIFNUM
    59 #define USE_SIOCGIFNUM 1
    60 #endif
    61
    62 #ifdef TRUCLUSTER  /* Tru64 Cluster Alias support */
    63
    64 #include <clua/clua.h>
    65 #include <sys/clu.h>
    66
    67 static clua_status_t (*clua_getaliasaddress_vector) (struct sockaddr *, int *);
    68 static char *(*clua_error_vector) (clua_status_t);
    69
    70 #define clua_getaliasaddress (*clua_getaliasaddress_vector)
    71 #define clua_error (*clua_error_vector)
    72
    73 struct clucall_vector clua_vectors[] = {
    74        { "clua_getaliasaddress", &clua_getaliasaddress_vector },
    75        { "clua_error", &clua_error_vector },
    76        { NULL,    NULL }              /* END OF LIST */
    77 };
    78
    79 #endif /* TRUCLUSTER */
    80
    81 UInt32                          SocketUtils::sNumIPAddrs = 0;
    82 SocketUtils::IPAddrInfo*        SocketUtils::sIPAddrInfoArray = NULL;
    83 OSMutex SocketUtils::sMutex;
    84
    85 #if __FreeBSD__
    86
    87 //Complete rewrite for FreeBSD.
    88 //The non-FreeBSD version really needs to be rewritten - it's a bit of a mess...
    89 void SocketUtils::Initialize(Bool16 lookupDNSName)
    90 {
    91    struct ifaddrs* ifap;
    92    struct ifaddrs* currentifap;
    93    struct sockaddr_in* sockaddr;
    94    int result = 0;
    95
    96    result = getifaddrs(&ifap);
    97
    98    //Count them first
    99    currentifap = ifap;
    100    while( currentifap != NULL )
    101    {
    102        sockaddr = (struct sockaddr_in*)currentifap->ifa_addr;
    103        if (sockaddr->sin_family == AF_INET)
    104            sNumIPAddrs++;
    105        currentifap = currentifap->ifa_next;
    106    }
    107
    108
    109    //allocate the IPAddrInfo array. Unfortunately we can't allocate this
    110    //array the proper way due to a GCC bug
    111    UInt8* addrInfoMem = new UInt8[sizeof(IPAddrInfo) * sNumIPAddrs];
    112    ::memset(addrInfoMem, 0, sizeof(IPAddrInfo) * sNumIPAddrs);
    113    sIPAddrInfoArray = (IPAddrInfo*)addrInfoMem;
    114
    115    int addrArrayIndex = 0;
    116    currentifap = ifap;
    117    while( currentifap != NULL )
    118    {
    119        sockaddr = (struct sockaddr_in*)currentifap->ifa_addr;
    120
    121        if (sockaddr->sin_family == AF_INET)
    122        {
    123            char* theAddrStr = ::inet_ntoa(sockaddr->sin_addr);
    124
    125            //store the IP addr
    126            sIPAddrInfoArray[addrArrayIndex].fIPAddr = ntohl(sockaddr->sin_addr.s_addr);
    127
    128            //store the IP addr as a string
    129            sIPAddrInfoArray[addrArrayIndex].fIPAddrStr.Len = ::strlen(theAddrStr);
    130            sIPAddrInfoArray[addrArrayIndex].fIPAddrStr.Ptr = new char[sIPAddrInfoArray[addrArrayIndex].fIPAddrStr.Le        n + 2];
    131            ::strcpy(sIPAddrInfoArray[addrArrayIndex].fIPAddrStr.Ptr, theAddrStr);
    132
    133            struct hostent* theDNSName = NULL;
    134            if (lookupDNSName) //convert this addr to a dns name, and store it
    135            {  theDNSName = ::gethostbyaddr((char *)&sockaddr->sin_addr, sizeof(sockaddr->sin_addr), AF_INET);
    136            }
    137
    138            if (theDNSName != NULL)
    139            {
    140                sIPAddrInfoArray[addrArrayIndex].fDNSNameStr.Len = ::strlen(theDNSName->h_name);
    141                sIPAddrInfoArray[addrArrayIndex].fDNSNameStr.Ptr = new char[sIPAddrInfoArray[addrArrayIndex].fDNSName        Str.Len + 2];
    142                ::strcpy(sIPAddrInfoArray[addrArrayIndex].fDNSNameStr.Ptr, theDNSName->h_name);
    143            }
    144            else
    145            {
    146                //if we failed to look up the DNS name, just store the IP addr as a string
    147                sIPAddrInfoArray[addrArrayIndex].fDNSNameStr.Len = sIPAddrInfoArray[addrArrayIndex].fIPAddrStr.Len;
    148                sIPAddrInfoArray[addrArrayIndex].fDNSNameStr.Ptr = new char[sIPAddrInfoArray[addrArrayIndex].fDNSName        Str.Len + 2];
    149                ::strcpy(sIPAddrInfoArray[addrArrayIndex].fDNSNameStr.Ptr, sIPAddrInfoArray[addrArrayIndex].fIPAddrSt        r.Ptr);
    150            }
    151
    152            addrArrayIndex++;
    153        }
    154
    155        currentifap = currentifap->ifa_next;
    156    }
    157
    158
    159 }
    160
    161 #else //__FreeBSD__
    162
    163 //Version for all non-FreeBSD platforms.
    164
    165 void SocketUtils::Initialize(Bool16 lookupDNSName)
    166 {
    167 #if defined(__Win32__) || defined(USE_SIOCGIFNUM)
    168
    169    int tempSocket = ::socket(AF_INET, SOCK_DGRAM, 0);
    170    if (tempSocket == -1)
    171        return;
    172
    173 #ifdef __Win32__
    174
    175    static const UInt32 kMaxAddrBufferSize = 2048;
    176    char inBuffer[kMaxAddrBufferSize];
    177    char outBuffer[kMaxAddrBufferSize];
    178    UInt32 theReturnedSize = 0;
    179
    180    //
    181    // Use the WSAIoctl function call to get a list of IP addresses
    182    int theErr = ::WSAIoctl(    tempSocket, SIO_GET_INTERFACE_LIST,
    183                                inBuffer, kMaxAddrBufferSize,
    184                                outBuffer, kMaxAddrBufferSize,
    185                                &theReturnedSize,
    186                                NULL,
    187                                NULL);
    188    Assert(theErr == 0);
    189    if (theErr != 0)
    190        return;
    191
    192    Assert((theReturnedSize % sizeof(INTERFACE_INFO)) == 0);
    193    LPINTERFACE_INFO addrListP = (LPINTERFACE_INFO)&outBuffer[0];
    194
    195    sNumIPAddrs = theReturnedSize / sizeof(INTERFACE_INFO);
    196 #else
    197 #if defined(USE_SIOCGIFNUM)
    198    if (::ioctl(tempSocket, SIOCGIFNUM, (char*)&sNumIPAddrs) == -1)
    199    {
    200 #ifdef MAXIFS
    201        sNumIPAddrs = MAXIFS;
    202 #else
    203        sNumIPAddrs = 64;
    204 #endif
    205    }
    206 #else
    207 #error
    208 #endif
    209    struct ifconf ifc;
    210    ::memset(&ifc,0,sizeof(ifc));
    211    ifc.ifc_len = sNumIPAddrs * sizeof(struct ifreq);
    212    ifc.ifc_buf = (caddr_t)new struct ifreq[sNumIPAddrs];
    213    Assert(ifc.ifc_buf != NULL);
    214
    215    ::memset(ifc.ifc_buf, '\0', ifc.ifc_len);
    216    int theErr = ::ioctl(tempSocket, SIOCGIFCONF, (char*)&ifc);
    217    Assert(theErr == 0);
    218    if (theErr != 0)
    219        return;
    220    struct ifreq* ifr = (struct ifreq*)ifc.ifc_buf;
    221 #endif
    222
    223    //allocate the IPAddrInfo array. Unfortunately we can't allocate this
    224    //array the proper way due to a GCC bug
    225    UInt8* addrInfoMem = new UInt8[sizeof(IPAddrInfo) * sNumIPAddrs];
    226    ::memset(addrInfoMem, 0, sizeof(IPAddrInfo) * sNumIPAddrs);
    227    sIPAddrInfoArray = (IPAddrInfo*)addrInfoMem;
    228
    229    //for (UInt32 addrCount = 0; addrCount < sNumIPAddrs; addrCount++)
    230    UInt32 currentIndex = 0;
    231    for (UInt32 theIfCount = sNumIPAddrs, addrCount = 0;
    232          addrCount < theIfCount; addrCount++)
    233    {
    234 #ifdef __Win32__
    235        // We *should* count the loopback interface as a valid interface.
    236        //if (addrListP[addrCount].iiFlags & IFF_LOOPBACK)
    237        //{
    238            // Don't count loopback addrs
    239        //  sNumIPAddrs--;
    240        //  continue;
    241        //}
    242        //if (addrListP[addrCount].iiFlags & IFF_LOOPBACK)
    243        //  if (lookupDNSName) // The playlist broadcaster doesn't care
    244        //      Assert(addrCount > 0); // If the loopback interface is interface 0, we've got problems
    245
    246        struct sockaddr_in* theAddr = (struct sockaddr_in*)&addrListP[addrCount].iiAddress;
    247 #elif defined(USE_SIOCGIFNUM)
    248        if (ifr[addrCount].ifr_addr.sa_family != AF_INET)
    249        {
    250            sNumIPAddrs--;
    251            continue;
    252        }
    253        struct ifreq ifrf;
    254        ::memset(&ifrf,0,sizeof(ifrf));
    255        ::strncpy(ifrf.ifr_name, ifr[addrCount].ifr_name, sizeof(ifrf.ifr_name));
    256        theErr = ::ioctl(tempSocket, SIOCGIFFLAGS, (char *) &ifrf);
    257        Assert(theErr != -1);
    258
    259 #ifndef __solaris__
    260        /* Skip things which aren't interesting */
    261        if ((ifrf.ifr_flags & IFF_UP) == 0 ||
    262            (ifrf.ifr_flags & (IFF_BROADCAST | IFF_POINTOPOINT)) == 0)
    263        {
    264            sNumIPAddrs--;
    265            continue;
    266        }
    267        if (ifrf.ifr_flags & IFF_LOOPBACK)
    268        {
    269            Assert(addrCount > 0); // If the loopback interface is interface 0, we've got problems
    270        }
    271 #endif
    272
    273        struct sockaddr_in* theAddr = (struct sockaddr_in*)&ifr[addrCount].ifr_addr;
    274    #if 0
    275        puts(ifr[addrCount].ifr_name);
    276    #endif
    277 #else
    278 #error
    279 #endif
    280
    281        char* theAddrStr = ::inet_ntoa(theAddr->sin_addr);
    282
    283        //store the IP addr
    284        sIPAddrInfoArray[currentIndex].fIPAddr = ntohl(theAddr->sin_addr.s_addr);
    285
    286        //store the IP addr as a string
    287        sIPAddrInfoArray[currentIndex].fIPAddrStr.Len = ::strlen(theAddrStr);
    288        sIPAddrInfoArray[currentIndex].fIPAddrStr.Ptr = new char[sIPAddrInfoArray[currentIndex].fIPAddrStr.Len + 2];
    289        ::strcpy(sIPAddrInfoArray[currentIndex].fIPAddrStr.Ptr, theAddrStr);
    290
    291
    292        struct hostent* theDNSName = NULL;
    293        if (lookupDNSName) //convert this addr to a dns name, and store it
    294        {  theDNSName = ::gethostbyaddr((char *)&theAddr->sin_addr, sizeof(theAddr->sin_addr), AF_INET);
    295        }
    296
    297        if (theDNSName != NULL)
    298        {
    299            sIPAddrInfoArray[currentIndex].fDNSNameStr.Len = ::strlen(theDNSName->h_name);
    300            sIPAddrInfoArray[currentIndex].fDNSNameStr.Ptr = new char[sIPAddrInfoArray[currentIndex].fDNSNameStr.Len        + 2];
    301            ::strcpy(sIPAddrInfoArray[currentIndex].fDNSNameStr.Ptr, theDNSName->h_name);
    302        }
    303        else
    304        {
    305            //if we failed to look up the DNS name, just store the IP addr as a string
    306            sIPAddrInfoArray[currentIndex].fDNSNameStr.Len = sIPAddrInfoArray[currentIndex].fIPAddrStr.Len;
    307            sIPAddrInfoArray[currentIndex].fDNSNameStr.Ptr = new char[sIPAddrInfoArray[currentIndex].fDNSNameStr.Len        + 2];
    308            ::strcpy(sIPAddrInfoArray[currentIndex].fDNSNameStr.Ptr, sIPAddrInfoArray[currentIndex].fIPAddrStr.Ptr);
    309        }
    310        //move onto the next array index
    311        currentIndex++;
    312
    313    }
    314 #ifdef __Win32__
    315    ::closesocket(tempSocket);
    316 #elif defined(USE_SIOCGIFNUM)
    317    delete[] ifc.ifc_buf;
    318    ::close(tempSocket);
    319 #else
    320 #error
    321 #endif
    322
    323 #else // !__Win32__
    324
    325    //Most of this code is similar to the SIOCGIFCONF code presented in Stevens,
    326    //Unix Network Programming, section 16.6
    327
    328    //Use the SIOCGIFCONF ioctl call to iterate through the network interfaces
    329    static const UInt32 kMaxAddrBufferSize = 2048;
    330
    331    struct ifconf ifc;
    332    ::memset(&ifc,0,sizeof(ifc));
    333    struct ifreq* ifr;
    334    char buffer[kMaxAddrBufferSize];
    335
    336    int tempSocket = ::socket(AF_INET, SOCK_DGRAM, 0);
    337    if (tempSocket == -1)
    338        return;
    339
    340    ifc.ifc_len = kMaxAddrBufferSize;
    341    ifc.ifc_buf = buffer;
    342
    343 #if __linux__ || __linuxppc__ || __solaris__ || __MacOSX__ || __sgi__ || __osf__
    344    int err = ::ioctl(tempSocket, SIOCGIFCONF, (char*)&ifc);
    345 #elif __FreeBSD__
    346    int err = ::ioctl(tempSocket, OSIOCGIFCONF, (char*)&ifc);
    347 #else
    348    #error
    349 #endif
    350    if (err == -1)
    351        return;
    352
    353 #if __FreeBSD__
    354    int netdev1, netdev2;
    355    struct ifreq *netdevifr;
    356    netdevifr = ifc.ifc_req;
    357    netdev1 = ifc.ifc_len / sizeof(struct ifreq);
    358    for (netdev2=netdev1-1; netdev2>=0; netdev2--)
    359        {
    360        if (ioctl(tempSocket, SIOCGIFADDR, &netdevifr[netdev2]) != 0)
    361            continue;
    362        }
    363 #endif
    364
    365    ::close(tempSocket);
    366    tempSocket = -1;
    367
    368    //walk through the list of IP addrs twice. Once to find out how many,
    369    //the second time to actually grab their information
    370    char* ifReqIter = NULL;
    371    sNumIPAddrs = 0;
    372
    373    for (ifReqIter = buffer; ifReqIter < (buffer + ifc.ifc_len);)
    374    {
    375        ifr = (struct ifreq*)ifReqIter;
    376        if (!SocketUtils::IncrementIfReqIter(&ifReqIter, ifr))
    377            return;
    378
    379        // Some platforms have lo as the first interface, so we have code to
    380        // work around this problem below
    381        //if (::strncmp(ifr->ifr_name, "lo", 2) == 0)
    382        //  Assert(sNumIPAddrs > 0); // If the loopback interface is interface 0, we've got problems
    383
    384        //Only count interfaces in the AF_INET family.
    385        if (ifr->ifr_addr.sa_family == AF_INET)
    386            sNumIPAddrs++;
    387    }
    388
    389 #ifdef TRUCLUSTER
    390
    391    int clusterAliases = 0;
    392
    393    if (clu_is_member())
    394    {
    395        /* loading the vector table */
    396      if (clua_getaliasaddress_vector == NULL)
    397      {
    398        clucall_stat    clustat;
    399        struct sockaddr_in  sin;
    400
    401        clustat = clucall_load("libclua.so", clua_vectors);
    402        int context = 0;
    403        clua_status_t      addr_err;
    404
    405        if (clua_getaliasaddress_vector != NULL)
    406          while ( (addr_err = clua_getaliasaddress
    407              ((struct sockaddr*)&sin, &context)) == CLUA_SUCCESS )
    408          {
    409        sNumIPAddrs++;
    410        clusterAliases++;
    411          }
    412      }
    413
    414    }
    415
    416 #endif // TRUCLUSTER
    417
    418    //allocate the IPAddrInfo array. Unfortunately we can't allocate this
    419    //array the proper way due to a GCC bug
    420    UInt8* addrInfoMem = new UInt8[sizeof(IPAddrInfo) * sNumIPAddrs];
    421    ::memset(addrInfoMem, 0, sizeof(IPAddrInfo) * sNumIPAddrs);
    422    sIPAddrInfoArray = (IPAddrInfo*)addrInfoMem;
    423
    424    //Now extract all the necessary information about each interface
    425    //and put it into the array
    426    UInt32 currentIndex = 0;
    427
    428 #ifdef TRUCLUSTER
    429        // Do these cluster aliases first so they'll be first in the list
    430        if (clusterAliases > 0)
    431        {
    432                int context = 0;
    433                struct sockaddr_in sin;
    434                clua_status_t      addr_err;
    435
    436                while ( (addr_err = clua_getaliasaddress ((struct sockaddr*)&sin, &context)) == CLUA_SUCCESS )
    437                {
    438                        char* theAddrStr = ::inet_ntoa(sin.sin_addr);
    439
    440                        //store the IP addr
    441                        sIPAddrInfoArray[currentIndex].fIPAddr = ntohl(sin.sin_addr.s_addr);
    442
    443                        //store the IP addr as a string
    444                        sIPAddrInfoArray[currentIndex].fIPAddrStr.Len = ::strlen(theAddrStr);
    445                        sIPAddrInfoArray[currentIndex].fIPAddrStr.Ptr = new char[sIPAddrInfoArray[currentIndex].fIPAd        drStr.Len + 2];
    446                        ::strcpy(sIPAddrInfoArray[currentIndex].fIPAddrStr.Ptr, theAddrStr);
    447
    448                        //convert this addr to a dns name, and store it
    449                        struct hostent* theDNSName = ::gethostbyaddr((char *)&sin.sin_addr,
    450                                                                                        sizeof(sin.sin_addr), AF_INET        );
    451                        if (theDNSName != NULL)
    452                        {
    453                                sIPAddrInfoArray[currentIndex].fDNSNameStr.Len = ::strlen(theDNSName->h_name);
    454                                sIPAddrInfoArray[currentIndex].fDNSNameStr.Ptr = new char[sIPAddrInfoArray[currentInd        ex].fDNSNameStr.Len + 2];
    455                                ::strcpy(sIPAddrInfoArray[currentIndex].fDNSNameStr.Ptr, theDNSName->h_name);
    456                        }
    457                        else
    458                        {
    459                                //if we failed to look up the DNS name, just store the IP addr as a string
    460                                sIPAddrInfoArray[currentIndex].fDNSNameStr.Len = sIPAddrInfoArray[currentIndex].fIPAd        drStr.Len;
    461                                sIPAddrInfoArray[currentIndex].fDNSNameStr.Ptr = new char[sIPAddrInfoArray[currentInd        ex].fDNSNameStr.Len + 2];
    462                                ::strcpy(sIPAddrInfoArray[currentIndex].fDNSNameStr.Ptr, sIPAddrInfoArray[currentInde        x].fIPAddrStr.Ptr);
    463                        }
    464
    465                        currentIndex++;
    466                }
    467        }
    468 #endif // TRUCLUSTER
    469
    470    for (ifReqIter = buffer; ifReqIter < (buffer + ifc.ifc_len);)
    471    {
    472        ifr = (struct ifreq*)ifReqIter;
    473        if (!SocketUtils::IncrementIfReqIter(&ifReqIter, ifr))
    474        {
    475            Assert(0);//we should have already detected this error
    476            return;
    477        }
    478
    479        //Only count interfaces in the AF_INET family
    480        if (ifr->ifr_addr.sa_family == AF_INET)
    481        {
    483            char* theAddrStr = ::inet_ntoa(addrPtr->sin_addr);
    484
    485            //store the IP addr
    486            sIPAddrInfoArray[currentIndex].fIPAddr = ntohl(addrPtr->sin_addr.s_addr);
    487
    488            //store the IP addr as a string
    489            sIPAddrInfoArray[currentIndex].fIPAddrStr.Len = ::strlen(theAddrStr);
    490            sIPAddrInfoArray[currentIndex].fIPAddrStr.Ptr = new char[sIPAddrInfoArray[currentIndex].fIPAddrStr.Len +        2];
    491            ::strcpy(sIPAddrInfoArray[currentIndex].fIPAddrStr.Ptr, theAddrStr);
    492
    493            struct hostent* theDNSName = NULL;
    494            if (lookupDNSName) //convert this addr to a dns name, and store it
    495            {  theDNSName = ::gethostbyaddr((char *)&addrPtr->sin_addr, sizeof(addrPtr->sin_addr), AF_INET);
    496            }
    497
    498            if (theDNSName != NULL)
    499            {
    500                sIPAddrInfoArray[currentIndex].fDNSNameStr.Len = ::strlen(theDNSName->h_name);
    501                sIPAddrInfoArray[currentIndex].fDNSNameStr.Ptr = new char[sIPAddrInfoArray[currentIndex].fDNSNameStr.        Len + 2];
    502                ::strcpy(sIPAddrInfoArray[currentIndex].fDNSNameStr.Ptr, theDNSName->h_name);
    503            }
    504            else
    505            {
    506                //if we failed to look up the DNS name, just store the IP addr as a string
    507                sIPAddrInfoArray[currentIndex].fDNSNameStr.Len = sIPAddrInfoArray[currentIndex].fIPAddrStr.Len;
    508                sIPAddrInfoArray[currentIndex].fDNSNameStr.Ptr = new char[sIPAddrInfoArray[currentIndex].fDNSNameStr.        Len + 2];
    509                ::strcpy(sIPAddrInfoArray[currentIndex].fDNSNameStr.Ptr, sIPAddrInfoArray[currentIndex].fIPAddrStr.Pt        r);
    510            }
    511
    512            //move onto the next array index
    513            currentIndex++;
    514        }
    515    }
    516
    517    Assert(currentIndex == sNumIPAddrs);
    518 #endif
    519
    520    //
    521    // If LocalHost is the first element in the array, switch it to be the second.
    522    // The first element is supposed to be the "default" interface on the machine,
    523    // which should really always be en0.
    524    if ((sNumIPAddrs > 1) && (::strcmp(sIPAddrInfoArray[0].fIPAddrStr.Ptr, "127.0.0.1") == 0))
    525    {
    526        UInt32 tempIP = sIPAddrInfoArray[1].fIPAddr;
    527        sIPAddrInfoArray[1].fIPAddr = sIPAddrInfoArray[0].fIPAddr;
    528        sIPAddrInfoArray[0].fIPAddr = tempIP;
    529        StrPtrLen tempIPStr(sIPAddrInfoArray[1].fIPAddrStr);
    530        sIPAddrInfoArray[1].fIPAddrStr = sIPAddrInfoArray[0].fIPAddrStr;
    531        sIPAddrInfoArray[0].fIPAddrStr = tempIPStr;
    532        StrPtrLen tempDNSStr(sIPAddrInfoArray[1].fDNSNameStr);
    533        sIPAddrInfoArray[1].fDNSNameStr = sIPAddrInfoArray[0].fDNSNameStr;
    534        sIPAddrInfoArray[0].fDNSNameStr = tempDNSStr;
    535    }
    536 }
    537 #endif  //__FreeBSD__
    538
    539
    540
    541 #ifndef __Win32__
    542 Bool16 SocketUtils::IncrementIfReqIter(char** inIfReqIter, ifreq* ifr)
    543 {
    544    //returns true if successful, false otherwise
    545
    546 #if __MacOSX__
    547    *inIfReqIter += sizeof(ifr->ifr_name) + ifr->ifr_addr.sa_len;
    548
    549    //if the length of the addr is 0, use the family to determine
    550    //what the addr size is
    551    if (ifr->ifr_addr.sa_len == 0)
    552 #else
    553    *inIfReqIter += sizeof(ifr->ifr_name) + 0;
    554 #endif
    555    {
    556        switch (ifr->ifr_addr.sa_family)
    557        {
    558            case AF_INET:
    559                *inIfReqIter += sizeof(struct sockaddr_in);
    560                break;
    561            default:
    562                *inIfReqIter += sizeof(struct sockaddr);
    563 //              Assert(0);
    564 //              sNumIPAddrs = 0;
    565 //              return false;
    566        }
    567    }
    568    return true;
    569 }
    570 #endif
    571
    572 Bool16 SocketUtils::IsMulticastIPAddr(UInt32 inAddress)
    573 {
    574    return ((inAddress>>8) & 0x00f00000) == 0x00e00000; //  multicast addresses == "class D" == 0xExxxxxxx == 1,1,1,0        ,<28 bits>
    575 }
    576
    577 Bool16 SocketUtils::IsLocalIPAddr(UInt32 inAddress)
    578 {
    579    for (UInt32 x = 0; x < sNumIPAddrs; x++)
    580        if (sIPAddrInfoArray[x].fIPAddr == inAddress)
    581            return true;
    582    return false;
    583 }
    584
    585 void SocketUtils::ConvertAddrToString(const struct in_addr& theAddr, StrPtrLen* ioStr)
    586 {
    587    //re-entrant version of code below
    588    //inet_ntop(AF_INET, &theAddr, ioStr->Ptr, ioStr->Len);
    589    //ioStr->Len = ::strlen(ioStr->Ptr);
    590
    591    sMutex.Lock();
    592    char* addr = inet_ntoa(theAddr);
    593    strcpy(ioStr->Ptr, addr);
    594    ioStr->Len = ::strlen(ioStr->Ptr);
    595    sMutex.Unlock();
    596 }
    597
    598 UInt32 SocketUtils::ConvertStringToAddr(const char* inAddrStr)
    599 {
    600    return ntohl(::inet_addr(inAddrStr));
    601 }
    602

---

How do I declare a variable of the right type, then do a memcpy() in this case?

First you find the right forum. C++ code does not belong on the C forum.


Quzah.

quzah


DSS is a mix of C/C++ code, so originally I've posted this question to C and C++ forums alltogether, but Salem told to not create double posts.

People started to help me here and my question is a continuation of their suggestions.

First thing would be for you to annotate the listing with the line numbers which are causing you problems.

Yeah, moved back to the C++ forum.

Hello Salem ,

I've annotated the listing with the line numbers (see above).

Below I'll paste the SocketUtils.h in case you need reference to this file also:

Code:

---


    26    File:      SocketUtils.h
    27
    28    Contains:  Some static routines for dealing with networking
    29
    30
    31 */
    32
    33 #ifndef __SOCKETUTILS_H__
    34 #define __SOCKETUTILS_H__
    35
    36 #ifndef __Win32__
    37 #include <sys/socket.h>
    38 #include <netinet/in.h>
    39 #include <net/if.h>
    40 #endif
    41
    42 #include "ev.h"
    43
    44 #include "OSHeaders.h"
    45 #include "MyAssert.h"
    46 #include "StrPtrLen.h"
    47 #include "OSMutex.h"
    48
    49 #ifdef __solaris__
    50    #ifndef INADDR_NONE
    51        #define INADDR_NONE    0xffffffff      /* -1 return from inet_addr */
    52    #endif
    53 #endif
    54
    55 class SocketUtils
    56 {
    57    public:
    58
    59        // Call initialize before using any socket functions.
    60        // (pass true for lookupDNSName if you want the hostname
    61        // looked up via DNS during initialization -- %%sfu)
    62        static void Initialize(Bool16 lookupDNSName = true);
    63
    64        //static utility routines
    65        static Bool16  IsMulticastIPAddr(UInt32 inAddress);
    66        static Bool16  IsLocalIPAddr(UInt32 inAddress);
    67
    68        //This function converts an integer IP address to a dotted-decimal string.
    69        //This function is NOT THREAD SAFE!!!
    70        static void ConvertAddrToString(const struct in_addr& theAddr, StrPtrLen* outAddr);
    71
    72        // This function converts a dotted-decimal string IP address to a UInt32
    73        static UInt32 ConvertStringToAddr(const char* inAddr);
    74
    75        //You can get at all the IP addrs and DNS names on this machine this way
    76        static UInt32      GetNumIPAddrs() { return sNumIPAddrs; }
    77        static inline UInt32        GetIPAddr(UInt32 inAddrIndex);
    78        static inline StrPtrLen*    GetIPAddrStr(UInt32 inAddrIndex);
    79        static inline StrPtrLen*    GetDNSNameStr(UInt32 inDNSIndex);
    80
    81    private:
    82
    83        //Utility function used by Initialize
    84 #ifndef __Win32__
    85        static Bool16 IncrementIfReqIter(char** inIfReqIter, ifreq* ifr);
    86 #endif
    87        //For storing relevent information about each IP interface
    88        struct IPAddrInfo
    89        {
    90            UInt32      fIPAddr;
    91            StrPtrLen  fIPAddrStr;
    92            StrPtrLen  fDNSNameStr;
    93        };
    94
    95        static IPAddrInfo*              sIPAddrInfoArray;
    96        static UInt32                  sNumIPAddrs;
    97        static OSMutex                  sMutex;
    98 };
    99
    100 inline UInt32  SocketUtils::GetIPAddr(UInt32 inAddrIndex)
    101 {
    102    Assert(sIPAddrInfoArray != NULL);
    103    Assert(inAddrIndex < sNumIPAddrs);
    104    return sIPAddrInfoArray[inAddrIndex].fIPAddr;
    105 }
    106
    107 inline StrPtrLen*  SocketUtils::GetIPAddrStr(UInt32 inAddrIndex)
    108 {
    109    Assert(sIPAddrInfoArray != NULL);
    110    Assert(inAddrIndex < sNumIPAddrs);
    111    return &sIPAddrInfoArray[inAddrIndex].fIPAddrStr;
    112 }
    113
    114 inline StrPtrLen*  SocketUtils::GetDNSNameStr(UInt32 inDNSIndex)
    115 {
    116    Assert(sIPAddrInfoArray != NULL);
    117    Assert(inDNSIndex < sNumIPAddrs);
    118    return &sIPAddrInfoArray[inDNSIndex].fDNSNameStr;
    119 }
    120
    121 #endif // __SOCKETUTILS_H__
    122

---

> SocketUtils.cpp:375: warning: cast from `char*' to `ifreq*' increases required alignment of target type
> 375 ifr = (struct ifreq*)ifReqIter;
Would become

Code:

---

struct ifreq temp;
memcpy( &temp, ifReqIter, sizeof temp );
ifr = &temp;

---

Thanks man,

Could you please give me an example here also for:

Code:

---

SocketUtils.cpp:422: warning: cast from `UInt8*' to `SocketUtils::IPAddrInfo*' increases required alignment of target type

SocketUtils.cpp:482: warning: cast from `sockaddr*' to `sockaddr_in*' increases required alignment of target type

---

It's the same example.

Hello All,

I keep fixing misaligned statements as Salem suggested.

But now I have some statement I can't get working :(
On line number 112 I got this while compiling -

Code:

---

RTCPUtilitiesLib/RTCPSRPacket.h: In member function `void RTCPSRPacket::SetSSRC(UInt32)':
RTCPUtilitiesLib/RTCPSRPacket.h:112: warning: cast from `char (*)[132]' to `UInt32*' increases required alignment of target type

---

This source is looking like this:

Code:

---

    109 inline void RTCPSRPacket::SetSSRC(UInt32 inSSRC)
    110 {
    111    // Set SSRC in SR
    112    ((UInt32*)&fSenderReportBuffer)[1] = htonl(inSSRC);

---

I've tried to fix this (112) line with:

UInt32 temp1; memcpy(&temp1, htonl(inSSRC), sizeof temp1); (&fSenderReportBuffer)[1]=&temp1;
and with -
UInt32 temp1; memcpy(&temp1, &htonl(inSSRC), sizeof temp1); (&fSenderReportBuffer)[1]=temp1;

But still I get these messages while compiling:

Code:

---

RTCPUtilitiesLib/RTCPSRPacket.h: In member function `void RTCPSRPacket::SetSSRC(UInt32)':
RTCPUtilitiesLib/RTCPSRPacket.h:112: error: incompatible types in assignment of `UInt32*' to `char[132]'

---

Any help/suggestions on how to fix this misaligned statement?

Guessing that fSenderReportBuffer is
char fSenderReportBuffer[132];

I would do

Code:

---

unsigned long temp = htonl(inSSRC);
memcpy ( &fSenderReportBuffer[sizeof(UInt32)], &temp, sizeof(temp) );

---

Thank you very much Salem.

Your solution is working!!!

Salem ,

Sorry for bothering with the same issue, but...

As you can see on the lines 112,115,119...

Code:

---

112:
((UInt32*)&fSenderReportBuffer)[1] = htonl(inSSRC);

115:
((UInt32*)&fSenderReportBuffer)[8] = htonl(inSSRC);

119:
((UInt32*)&fSenderReportBuffer)[(fSenderReportSize >> 2) + 1] = htonl(inSSRC);

---

We have different values inside
fSenderReportBuffer[here is the value that changes on all the lines]

Where should I insert the appropriate change so it would meet your solution for every line:

Code:

---

unsigned long temp = htonl(inSSRC);
memcpy ( &fSenderReportBuffer[sizeof(UInt32)], &temp, sizeof(temp) )

---

Hi,

Should this code

Code:

---

unsigned long temp = htonl(inSSRC);
memcpy ( &fSenderReportBuffer[sizeof(UInt32)], &temp, sizeof(temp) );

---

look like this on line 119? :

Code:

---

unsigned long temp = htonl(inSSRC);
memcpy ( &fSenderReportBuffer[(fSenderReportSize >> 2) + 1], &temp, sizeof(temp) );

---

or like this:

Code:

---

unsigned long temp = htonl(inSSRC);
memcpy ( &fSenderReportBuffer[sizeof(UInt32)], &temp, sizeof(temp) );
(&fSenderReportBuffer)[(fSenderReportSize >> 2) + 1]=temp;

---

> ((UInt32*)&fSenderReportBuffer)[1] = htonl(inSSRC);
Recall this line became
memcpy ( &fSenderReportBuffer[sizeof(UInt32)], &temp, sizeof(temp) );

More generally, I could have written
memcpy ( &fSenderReportBuffer[sizeof(UInt32)*1], &temp, sizeof(temp) );
where the 1 is the subscript you would like had the array been a proper array of UInt32.

Salem,

Thanks for the explanations.

Hi,

Continuing to fix misaligned statements and need some help.

1) I got this error:
Server.tproj/RTCPTask.cpp:95: warning: cast from `UDPDemuxerTask*' to `RTPStream*' increases required alignment of target type
In file included from Server.tproj/RTPSessionInterface.h:41,
from Server.tproj/RTPSession.h:48,
from Server.tproj/RTPSession.cpp:36:

This is how the source line looks like:

Code:

---

95  RTPStream* theStream = (RTPStream*)theDemuxer->GetTask(theRemoteAddr, theRemotePort);

---

I've tried to fix it with -

Code:

---

struct RTPStream temp; memcpy (&temp, theDemuxer->GetTask(theRemoteAddr, theRemotePort), sizeof temp); RTPStream* theStream =&temp;

---

or this -

Code:

---

RTPStream temp(theDemuxer->GetTask(theRemoteAddr,  theRemotePort)); RTPStream* theStream =&temp;

---

But I keep getting compilation errors like these:

Code:

---

Server.tproj/RTCPTask.cpp: In member function `virtual SInt64 RTCPTask::Run()':
Server.tproj/RTCPTask.cpp:95: error: no matching function for call to `RTPStream::RTPStream(UDPDemuxerTask&)'
Server.tproj/RTPStream.h:57: note: candidates are: RTPStream::RTPStream(const RTPStream&)
Server.tproj/RTPStream.h:66: note:                RTPStream::RTPStream(UInt32, RTPSessionInterface*)
make: *** [Server.tproj/RTCPTask.o] Error 1

---

That can I do here?

2) Another problem is like this:
I got htis error:

Code:

---

Server.tproj/RTPSessionInterface.cpp: In static member function `static void* RTPSessionInterface::TimeConnected(QTSSDictionary*, UInt32*)':
Server.tproj/RTPSessionInterface.cpp:277: warning: cast from `QTSSDictionary*' to `RTPSessionInterface*' increases required alignment of target type
Server.tproj/RTPSessionInterface.cpp: In static member function `static void* RTPSessionInterface::CurrentBitRate(QTSSDictionary*, UInt32*)':
Server.tproj/RTPSessionInterface.cpp:287: warning: cast from `QTSSDictionary*' to `RTPSessionInterface*' increases required alignment of target type
Server.tproj/RTPSessionInterface.cpp: In static member function `static void* RTPSessionInterface::PacketLossPercent(QTSSDictionary*, UInt32*)':
Server.tproj/RTPSessionInterface.cpp:298: warning: cast from `QTSSDictionary*' to `RTPSessionInterface*' increases required alignment of target type

---

This is how the source looks like -

Code:

---

    277    RTPSessionInterface* theSession = (RTPSessionInterface*)inSession;

    287    RTPSessionInterface* theSession = (RTPSessionInterface*)inSession;

    298    RTPSessionInterface* theSession = (RTPSessionInterface*)inSession;

---

I've tried to fix it like this -

Code:

---

277  struct RTPSessionInterface temp; memcpy (&temp, inSession, sizeof temp); RTPSessionInterface* theSession =&temp;
287  struct RTPSessionInterface temp1; memcpy (&temp1, inSession, sizeof temp1); RTPSessionInterface* theSession =&temp1;
298  struct RTPSessionInterface temp2; memcpy (&temp2, inSession, sizeof temp2); RTPSessionInterface* theSession =&temp2;

---

But keep getting errors for these fixes:

Code:

---

Server.tproj/RTPSessionInterface.cpp: In static member function `static void* RTPSessionInterface::TimeConnected(QTSSDictionary*, UInt32*)':
Server.tproj/RTPSessionInterface.cpp:277: error: cannot declare variable `temp' to be of type `RTPSessionInterface'
Server.tproj/RTPSessionInterface.cpp:277: error:  because the following virtual functions are abstract:
CommonUtilitiesLib/Task.h:94: error:  virtual SInt64 Task::Run()
Server.tproj/RTPSessionInterface.cpp: In static member function `static void* RTPSessionInterface::CurrentBitRate(QTSSDictionary*, UInt32*)':
Server.tproj/RTPSessionInterface.cpp:287: error: cannot declare variable `temp1' to be of type `RTPSessionInterface'
Server.tproj/RTPSessionInterface.cpp:287: error:  since type `RTPSessionInterface' has abstract virtual functions
Server.tproj/RTPSessionInterface.cpp: In static member function `static void* RTPSessionInterface::PacketLossPercent(QTSSDictionary*, UInt32*)':
Server.tproj/RTPSessionInterface.cpp:298: error: cannot declare variable `temp2' to be of type `RTPSessionInterface'
Server.tproj/RTPSessionInterface.cpp:298: error:  since type `RTPSessionInterface' has abstract virtual functions
make: *** [Server.tproj/RTPSessionInterface.o] Error 1

---

How can I fix these errors here?


Thanks in advance for your replies.

Whoa! Far too many casts! You're hiding the real errors.


For example, demuxer->GetTask obviously returns a UDPDemuxerTask*. Why do you try to asssign it to an RTPStream*? Is RTPStream a subclass of UDPDemuxerTask? Then use dynamic_cast. Otherwise you're just doing something totally illegal.

Ecactly the same issue in your second problem. The source is QTSSDictionary*, the target RTPSessionInterface*. What makes you think you can just assign them?

C++ is strongly typed for a reason.

This is not my code.

This is part of DSS (Darwin Streaming Server of Apple).
I'm just trying to fix some misaligned statements, which preventing to run DSS on my architecture.

I'm not a C++ programmer, just have a basic knowledge and trying to get some help/advice here.

Hello Salem,

I'm really lost with code (I've posted above on 07-08-2006, 10:31 AM).

Could you please review and tell/recommend me how to deal with it?

> Could you please review and tell/recommend me how to deal with it?
You really need to get in contact with the authors / maintainers at this point.

> warning: cast from `UDPDemuxerTask*' to `RTPStream*' increases required alignment of target type
Fixing alignment of say UINT32 is one thing, fixing class pointers is another.

Especially if both things are part of the same class heirarchy, and up/down casting is supposed to do "the right thing" by the rules of C++.
Understanding how those classes are supposed to interact is far more work than I'm prepared to take on at the moment - maybe someone else would help you if you'd care to post an announcement in the projects and recruitment board (if the author isn't willing to help). This is sounding like a significant task all of a sudden.


If this isn't happening, then something serious has gone wrong, and the approach so far just isn't going to work anymore IMO.

Are you still getting bus errors when you try and run what you've produced so far ?
That is, have you done enough so that it now runs when you turn off the alignment warning?

Hello Salem,

Thanks for your reply.
I still get "Bus Errors".

Seems to me that I should install Solaris 10 on that machine (DSS reported to compile and run on that OS).

Thanks for all your help :)