I am newbe in the Linux , I use gcc to compile the simple following code but it sai that the fmod() unreferenced . I guess that something wrong with the include file . But i do not know .
#include "stdio.h"
#include <math.h>
void main()
{
int i = fmod(12,2);
printf("%d",i);
}

and I use the simple command to compile : gcc check.c
And the error occur .
I use fedora and I use emacs check.c at the root directory .
Thank you and have nice day .

1) post titles with a descriptive topic, not "help!!!" or "help me"

2) post the exact error (copy it from the terminal) message

3) if its the error i think it is, try "gcc check.c -lm"

why "stdio.h" and not <stdio.h> ???
do you have the stdio.h file in this folder ???

you need to link the math library,

do this...

(I assume your file is called check.c?)

[quote]> gcc -o check check.c -lm
check.c: In function ‘main’:
check.c:4: warning: return type of ‘main’ is not ‘int’[/code]As mentioned previously it should, probably, read <math.h> and compile with
that will get rid of the error message that you were getting.

Removal of void from void main() will prevent of the warning about the return type of 'main'.
I will of course follow up on your comments too Billy. You're not noted for speaking without having something worthwhile to say however, and I would hate you to feel your efforts were wasted. A bit like casting Perl among . . . ( It's just not near the top of my reading list - oink! )

Doanhanam, you might also find it helpful to put a newline '\n' in the format string of printf. it will make it easier to read/notice the output, which otherwise will hide behind the your terminal monitor prompt.

Billy, any thoughts about about the return type of main(), can I assume that the default return type expected is int? ( More reading for me ).

I believe, that the default type for each and every function is int unless otherwise
specified.

I think
main()

maps to

int main(void)

but it's only a warning, just sling a return 0; on the end of the main.
it's good practice to return 0 for OK, otherwise non zero.
(this is to the operating system, of course internally in C the truth is reversed!!!)

Here's a good ref list: http://members.aol.com/wantondeb/#MAIN

thank you for the precious help . I have try and It runs correctly .
I am very happy to continue programming in Linux . In viet Nam , little programmers use Linux because they are used to Windows . My classmates seldom program on this environment . And I get more confident when joining this forum . Thank you a lot for all .
Have good day ! .

it's the same the world over.
leave them to their virus-scanners I say.

the art of unix programming