Thread: K&R chapter 8

Which OS do i need to successfully run programs from chapter 8 in K&R?

I saw they included "syscalls.h" in their first program, allowing them usage of read/write/open/close functions from the system.

Since im using Windows, do i have to install a UNIX OS? If so which one? And even then, do i need to install a special compiler to be able to use the mentioned system functions?

Code:

while((n = read(0, buf, BUFSIZE)) > 0)
        write(1, buf, n);

My compiler actually recognizes these functions - a bubble pops up with the arguments i have to write in when i write read (...) in the code window. But i dont know in which header they are. Im using Dev-C++.

Well it is definitely available in Linux (Ubuntu 9.10):

Code:

jeff@jeff-gate:~$ find /usr/include/ -name "*.h" | grep syscall
/usr/include/asm/vsyscall.h
/usr/include/syscall.h
/usr/include/linux/nfsd/syscall.h
/usr/include/bits/syscall.h
/usr/include/sys/syscall.h
jeff@jeff-gate:~$

However they might also be available in cygwin via GCC...

YMMV

Jeff

Do i need to include some special header in a UNIX C Compiler to use those system functions? If so which one?

Which compiler should i download on KUBUNTU OS? Thats the one im planning to use.

cygwin

Can you name the header? Havent found anything like this...

Originally Posted by Tool

Which compiler should i download on KUBUNTU OS? Thats the one im planning to use.

As in you are going to install Kubuntu? The standard compiler there is gcc and it is part of a basic install, I think, otherwise:

apt-cache search gcc

will give you a list, probably the package is just called "gcc.x86_64" or something. Ubuntu also has a graphical package manager, you can use that and search for "gcc".

But first just type "gcc" at the command-line, if it says "gcc: no input files" then it is already installed.

Originally Posted by Tool

And do i have to include a special header in the standard compiler in order to use read/write and other system functions?

You just have to use #include <syscall.h>

Btw, can i do it all from a VirtualBox Machine? I mean execute the programs.

Dunno!

Your source file is called whatever.c:

gcc -Wall whatever.c

"-Wall" is enable all warnings.

The executable will be by default "a.out". If you want to call it something else use:

gcc -Wall -o something_else whatever.c

ps. dos "dir" == unix "ls".

For info:
man ls
man gcc
man man

Takes deep breath.

OK Tool first I think the header you are looking for is unistd.h...see this (write is part of the POSIX standard):
write

Next, I thought you were on Windows so I suggested Cygwin which lets you compile unix-like programs for Windows...its not a header, more like a mini-environment on Windows providing many UNIX-like tools. However if you are running KUbuntu in a VirtualBox session..
1. Compiling will work just fine in VirtualBox, albeit like any virtualized environment, slower that if it ran on bare metal.
2. To run the compiler on any Linux, like MK said just run gcc (or g++ for C++). BUT if you are coming from a Windows back-ground and are used to the hand-holding, spoon-fed compilers there then what you are probably expecting is an IDE a la Visual Studio or Code::Blocks. Actually you can install CodeBlocks on Ubuntu (open a terminal and run sudo apt-get install codeblocks) or you can run KDevelop (sudo apt-get install kdevelop) which are both GUI front-ends for gcc/g++.
3. In any event, keep in mind that gcc is the *compiler* not the IDE front-end. You can run gcc from the terminal but like most free tools it demands that you know what you are doing