linux man page for syscall

SYSCALL(2)						     Linux Programmer's Manual							SYSCALL(2)

NAME
       syscall - indirect system call

SYNOPSIS
       #define _GNU_SOURCE	  /* or _BSD_SOURCE or _SVID_SOURCE */
       #include <unistd.h>
       #include <sys/syscall.h>   /* For SYS_xxx definitions */

       int syscall(int number, ...);

DESCRIPTION
       syscall()  performs the system call whose assembly language interface has the specified number with the specified arguments.  Symbolic con-
       stants for system calls can be found in the header file <sys/syscall.h>.

RETURN VALUE
       The return value is defined by the system call being invoked.  In general, a 0 return value indicates success.  A -1 return value indicates
       an error, and an error code is stored in errno.

NOTES
       syscall() first appeared in 4BSD.

EXAMPLE
       #define _GNU_SOURCE
       #include <unistd.h>
       #include <sys/syscall.h>
       #include <sys/types.h>

       int
       main(int argc, char *argv[])
       {
	   pid_t tid;

	   tid = syscall(SYS_gettid);
       }

SEE ALSO
       _syscall(2), intro(2), syscalls(2)

COLOPHON
       This  page is part of release 3.27 of the Linux man-pages project.  A description of the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

Linux								    2007-07-26								SYSCALL(2)