This document is a Mac OS X manual page. Manual pages are a command-line technology for providing documentation. You can view these manual pages locally using the man(1) command. These manual pages come from many different sources, and thus, have a variety of writing styles.

This manual page is associated with the Mac OS X developer tools. The software or headers described may not be present on your Mac OS X installation until you install the developer tools package. This package is available on your Mac OS X installation DVD, and the latest versions can be downloaded from developer.apple.com.

For more information about the manual page format, see the manual page for manpages(5).

SYSCALL(2)                  BSD System Calls 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 system call is useful for testing new sys-tem system
     tem 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