BSWAP(3) Linux Programmer's Manual BSWAP(3)

bswap_16, bswap_32, bswap_64 - reverse order of bytes

#include <byteswap.h>
uint16_t bswap_16(uint16_t x);
uint32_t bswap_32(uint32_t x);
uint64_t bswap_64(uint64_t x);

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

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

These functions always succeed.

These functions are GNU extensions.

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

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <inttypes.h>
#include <byteswap.h>
main(int argc, char *argv[])
    uint64_t x;
    if (argc != 2) {
        fprintf(stderr, "Usage: %s <num>\n", argv[0]);
    x = strtoull(argv[1], NULL, 0);
    printf("%#" PRIx64 " ==> %#" PRIx64 "\n", x, bswap_64(x));

byteorder(3), endian(3)

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2021-06-20 Linux