syscall — indirect system call
#define _GNU_SOURCE /* See feature_test_macros(7) */ #include <unistd.h> #include <sys/syscall.h> /* For SYS_xxx definitions */
int
syscall( |
int number, |
...) ; |
syscall
() is a small library
function that invokes the system call whose assembly language
interface has the specified number
with the specified
arguments. Employing syscall
()
is useful, for example, when invoking a system call that has
no wrapper function in the C library.
syscall
() saves CPU
registers before making the system call, restores the
registers upon return from the system call, and stores any
error code returned by the system call in errno(3) if an error
occurs.
Symbolic constants for system call numbers can be found in
the header file <
sys/syscall.h
>
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
.
#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); tid = syscall(SYS_tgkill, getpid(), tid); }
This page is part of release 3.42 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/.
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