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

NAME
     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 constants
     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 parameters is a
     64-bit argument to ensure that argument alignment is correct.  This sys-
     tem 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 gen-
     eral, 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.

OpenBSD 2.6                      June 16, 1993                               1