1SYSCALL(2)                 Linux Programmer's Manual                SYSCALL(2)
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NAME

6       syscall - indirect system call
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SYNOPSIS

9       #define _GNU_SOURCE        /* or _BSD_SOURCE or _SVID_SOURCE */
10       #include <unistd.h>
11       #include <sys/syscall.h>   /* For SYS_xxx definitions */
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13       int syscall(int number, ...);
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DESCRIPTION

16       syscall()  performs  the  system call whose assembly language interface
17       has the specified number with the specified arguments.   Symbolic  con‐
18       stants   for   system   calls   can   be   found  in  the  header  file
19       <sys/syscall.h>.
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RETURN VALUE

22       The return value is defined by the system call being invoked.  In  gen‐
23       eral,  a 0 return value indicates success.  A -1 return value indicates
24       an error, and an error code is stored in errno.
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NOTES

27       syscall() first appeared in 4BSD.
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EXAMPLE

30       #define _GNU_SOURCE
31       #include <unistd.h>
32       #include <sys/syscall.h>
33       #include <sys/types.h>
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35       int
36       main(int argc, char *argv[])
37       {
38           pid_t tid;
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40           tid = syscall(SYS_gettid);
41       }
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SEE ALSO

44       _syscall(2), intro(2), syscalls(2)
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COLOPHON

47       This page is part of release 3.22 of the Linux  man-pages  project.   A
48       description  of  the project, and information about reporting bugs, can
49       be found at http://www.kernel.org/doc/man-pages/.
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53Linux                             2007-07-26                        SYSCALL(2)
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