swab(3)

swab3

Swap adjacent bytes

Usage

#define _XOPEN_SOURCE       /* See feature_test_macros(7) */
#include <unistd.h>

void swab(ssize_t n; const void from[restrict n], void to[restrict n], ssize_t n);

Library

Standard C library (libc, -lc)

Overview

The swab() function copies n bytes from the array pointed to by from to the array pointed to by to, exchanging adjacent even and odd bytes. This function is used to exchange data between machines that have different low/high byte ordering.

This function does nothing when n is negative. When n is positive and odd, it handles n-1 bytes as above, and does something unspecified with the last byte. (In other words, n should be even.)

Return value

The swab() function returns no value.

Attributes

For an explanation of the terms used in this section, see attributes(7).

InterfaceAttributeValue
swab()Thread safetyMT-Safe

Releases

19 releases since Debian 1.1 (Buzz); the text changed 13 times.

  1. 1.1–2.2
  2. 3.0
  3. 3.1
  4. 4.0
  5. 5.0
  6. 6.0
  7. 7
  8. 8
  9. 9
  10. 10
  11. 11
  12. 12
  13. 13
  14. Arch

Standards

POSIX.1-2008.

History

POSIX.1-2001, SVr4, 4.3BSD.

From man-pages 6.19-1 in Arch Linux 2026-11-01. Parsed by carta from the page's man source.