bswap(3) — Linux manual page

bswap(3)                 Library Functions Manual                bswap(3)

NAME         top

       bswap_16, bswap_32, bswap_64 - reverse order of bytes

LIBRARY         top

       Standard C library (libc, -lc)

SYNOPSIS         top

       #include <byteswap.h>

       uint16_t bswap_16(uint16_t x);
       uint32_t bswap_32(uint32_t x);
       uint64_t bswap_64(uint64_t x);

DESCRIPTION         top

       These functions return a value in which the order of the bytes in
       their 2-, 4-, or 8-byte arguments is reversed.

RETURN VALUE         top

       These functions return the value of their argument with the bytes
       reversed.

ERRORS         top

       These functions always succeed.

STANDARDS         top

       GNU.

EXAMPLES         top

       The program below swaps the bytes of the 8-byte integer supplied
       as its command-line argument.  The following shell session
       demonstrates the use of the program:

           $ ./a.out 0x0123456789abcdef;
           0x123456789abcdef ==> 0xefcdab8967452301

   Program source

       #include <byteswap.h>
       #include <inttypes.h>
       #include <stdint.h>
       #include <stdio.h>
       #include <stdlib.h>

       int
       main(int argc, char *argv[])
       {
           uint64_t x;

           if (argc != 2) {
               fprintf(stderr, "Usage: %s <num>\n", argv[0]);
               exit(EXIT_FAILURE);
           }

           x = strtoull(argv[1], NULL, 0);
           printf("%#" PRIx64 " ==> %#" PRIx64 "\n", x, bswap_64(x));

           exit(EXIT_SUCCESS);
       }

SEE ALSO         top

       byteorder(3), endian(3)

COLOPHON         top

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Linux man-pages 6.15            2025-05-17                       bswap(3)

Pages that refer to this page: byteorder(3),  endian(3)

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