swab(3) — Linux manual page

swab(3)                  Library Functions Manual                 swab(3)

NAME         top

       swab - swap adjacent bytes

LIBRARY         top

       Standard C library (libc, -lc)

SYNOPSIS         top

       #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);

DESCRIPTION         top

       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         top

       The swab() function returns no value.

ATTRIBUTES         top

       For an explanation of the terms used in this section, see
       attributes(7).
       ┌──────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                            │ Attribute     │ Value   │
       ├──────────────────────────────────────┼───────────────┼─────────┤
       │ swab()                               │ Thread safety │ MT-Safe │
       └──────────────────────────────────────┴───────────────┴─────────┘

STANDARDS         top

       POSIX.1-2008.

HISTORY         top

       POSIX.1-2001, SVr4, 4.3BSD.

SEE ALSO         top

       bstring(3)

COLOPHON         top

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Linux man-pages 6.15            2025-06-28                        swab(3)

Pages that refer to this page: bzero(3),  memset(3)

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