syscall(2)

syscall2

Indirect system call

Usage

#include <sys/syscall.h>

#include <unistd.h>

int

syscall(int number, ...);

Overview

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⟩. This function 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.

Releases

155 releases since Mac OS X 10.0; the text changed 2 times.

  1. 10.0–10.5.8
  2. 10.6–10.11.6
  3. 10.12–26.5

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.

From xnu 12377.121.6 in macOS 26.5. Parsed by carta from the page's mdoc source.