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syscall(2) [opendarwin man page]

SYSCALL(2)						      BSD System Calls Manual							SYSCALL(2)

syscall, __syscall -- indirect system call SYNOPSIS
#include <sys/syscall.h> #include <unistd.h> int syscall(int number, ...); int __syscall(quad_t 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>. The __syscall form should be used when one or more of the parame- ters is a 64-bit argument to ensure that argument alignment is correct. This system call is useful for testing new system calls that do not have entries in the C library. RETURN VALUES
The return values are 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. BUGS
There is no way to simulate system calls that have multiple return values such as pipe(2). HISTORY
The syscall() function call appeared in 4.0BSD. 4th Berkeley Distribution June 16, 1993 4th Berkeley Distribution

Check Out this Related Man Page

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

syscall - indirect system call SYNOPSIS
#define _GNU_SOURCE /* See feature_test_macros(7) */ #include <unistd.h> #include <sys/syscall.h> /* For SYS_xxx definitions */ int syscall(int number, ...); DESCRIPTION
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>. 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); tid = syscall(SYS_tgkill, getpid(), tid); } SEE ALSO
_syscall(2), intro(2), syscalls(2) COLOPHON
This page is part of release 3.44 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at Linux 2012-08-14 SYSCALL(2)
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