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@(#)syscall.2 6.2 (Berkeley) 04/16/86

C 4 syscall - indirect system call

#include <syscall.h>

 "syscall(number, arg, ...)"     (VAX-11) 

Syscall performs the system call whose assembly language interface has the specified number, register arguments r0 and r1 and further arguments arg . Symbolic constants for system calls can be found in the header file <syscall.h>.

The r0 value of the system call is returned.

When the C-bit is set, syscall returns -1 and sets the external variable errno (see intro (2)). There is no way to simulate system calls such as pipe (2), which return values in register r1.