NAME

     syscall, __syscall — indirect system call

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <sys/syscall.h>
     #include <unistd.h>

     int
     syscall(int number, ...);

     off_t
     __syscall(quad_t number, ...);

DESCRIPTION

     The syscall() function 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 arguments 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.

HISTORY

     The syscall() function appeared in 4.0BSD.

BUGS

     There is no way to simulate system calls that have multiple return values such as pipe(2).