I need to use a char * buf which size augment gradually.
The way I do it is not working I guess that what crashes the program.
Do I need to Free it everytime or can I just Allocate a new size without Freeing it before?
Code:// global char * buf; while(1) { buf = (char*) GlobalAlloc(GMEM_FIXED, newsize); FunctionThatUses_buf(); GlobalFree(buf); Sleep(1000 * 30); }
Using Windows 10 with Code Blocks and MingW.
What do you mean 'uses'?
GlobalAlloc function (Windows)
GlobalAlloc returns a HANDLE, not a pointer.
Did you get a warning about this before throwing in a cast to make the compiler shut up?
Also,What's wrong with using new and delete?New applications should use the heap functions unless documentation states that a global function should be used.
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
If at first you don't succeed, try writing your phone number on the exam paper.
Ouh, thanks for clearing that up.
It uses the char * buf to write text to a file.
Yes I got a compile error cannot convert from 'HGLOBAL' to 'char *' but I thought it was normal with C++ compiler.
I thought "new" calls GlobalAlloc() thats why I used it. So than what's GlobalAlloc() is for?
Using Windows 10 with Code Blocks and MingW.
Althought I think new does use GlobalAlloc it is best to use new b/c it does far more than just call that method. Get into the habit of using new and delete.
GlobalAlloc() exists so that old programs that use it can keep working.Originally Posted by Ducky
Code://try //{ if (a) do { f( b); } while(1); else do { f(!b); } while(1); //}
It is also a good idea for an Operating System to have something like GlobalAlloc since memory allocation falls under its array of tasks.
GlobalAlloc is a legacy, windows specific OS API call that provides slightly more fine control over allocation than new, at the cost of portability. Don't use it.
It is too clear and so it is hard to see.
A dunce once searched for fire with a lighted lantern.
Had he known what fire was,
He could have cooked his rice much sooner.
Why are you using all these Win32 functions in the first place? What's wrong with the C++ standard library?
Well I read a lot of stuff and it confuses me sometimes.
I read somewhere that C++ functions call the lower level Win32 API functions so then why not just call them directly.
Using Windows 10 with Code Blocks and MingW.
All library functions are just a bunch of assembly instructions. Why not just write in assembly directly instead?
Now that would be pushing it, wouldn't it? ;-)
Using Windows 10 with Code Blocks and MingW.
but it follows your line of thinking. if you're learning C++, learn C++. learn win32 later.
I would say the same about what you are doing.
If you insist on using lower level functions just because higher level functions call them, then you might as well use assembly because all higher level functions are just a bunch of assembly instructions.
Of course higher level stuff calls lower level stuff. That's how all is built. You build and abstract the lower level stuff. By doing so, you get a better interface that is easier to use.
That is how C is built - by building on hardware. C++ builds on C. C#, Java, etc, also builds on C and C++.
If you can use higher level stuff, then do it. Don't lower yourself to the level of lower level stuff. This should go without saying.
