2016-04-21 11:07:01 +00:00
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.\" Copyright (C) 2016 Michael Kerrisk <mtk.manpages@gmail.com>
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.\"
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.\" %%%LICENSE_START(VERBATIM)
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" permission notice identical to this one.
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.\"
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
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.\" responsibility for errors or omissions, or for damages resulting from
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.\" have taken the same level of care in the production of this manual,
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.\" %%%LICENSE_END
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.\"
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.TH BSWAP 3 2016-04-21 "Linux" "Linux Programmer's Manual"
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.SH NAME
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bswap_16, bswap_32, bswap_64 \- reverse order of bytes
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.SH SYNOPSIS
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.nf
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.B #include <byteswap.h>
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_syscall.2, clock_getres.2, clone.2, copy_file_range.2, create_module.2, delete_module.2, fallocate.2, futex.2, get_kernel_syms.2, get_robust_list.2, getcpu.2, getdents.2, gettid.2, gettimeofday.2, getunwind.2, init_module.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl_userfaultfd.2, ioprio_set.2, kcmp.2, kexec_load.2, keyctl.2, link.2, llseek.2, memfd_create.2, mmap.2, mq_getsetattr.2, msgctl.2, msgget.2, open_by_handle_at.2, outb.2, perf_event_open.2, pivot_root.2, process_vm_readv.2, query_module.2, readdir.2, recvmmsg.2, rename.2, request_key.2, restart_syscall.2, rt_sigqueueinfo.2, s390_pci_mmio_write.2, s390_runtime_instr.2, sched_setattr.2, seccomp.2, select.2, select_tut.2, send.2, sendmmsg.2, set_thread_area.2, set_tid_address.2, sgetmask.2, shmop.2, sigaction.2, sigprocmask.2, splice.2, spu_create.2, spu_run.2, statx.2, subpage_prot.2, sync_file_range.2, syscall.2, sysctl.2, sysfs.2, tee.2, timer_create.2, timer_delete.2, timer_getoverrun.2, timer_settime.2, tkill.2, uselib.2, utimensat.2, vmsplice.2, wait.2, aio_init.3, asinh.3, atan2.3, atanh.3, backtrace.3, basename.3, bswap.3, bzero.3, catgets.3, catopen.3, dladdr.3, dlsym.3, endian.3, envz_add.3, erf.3, erfc.3, error.3, ferror.3, ffs.3, fgetc.3, fmemopen.3, fopen.3, fopencookie.3, fseek.3, ftw.3, futimes.3, getdate.3, getenv.3, getline.3, getlogin.3, getrpcent.3, getsubopt.3, getutmp.3, getw.3, gnu_get_libc_version.3, inet_net_pton.3, isalpha.3, lio_listio.3, makedev.3, malloc_get_state.3, malloc_stats.3, malloc_trim.3, malloc_usable_size.3, matherr.3, memchr.3, nextup.3, ntp_gettime.3, posix_madvise.3, program_invocation_name.3, pthread_atfork.3, pthread_attr_setaffinity_np.3, pthread_attr_setdetachstate.3, pthread_attr_setguardsize.3, pthread_attr_setinheritsched.3, pthread_attr_setschedparam.3, pthread_attr_setschedpolicy.3, pthread_attr_setscope.3, pthread_attr_setstack.3, pthread_attr_setstackaddr.3, pthread_attr_setstacksize.3, pthread_cleanup_push_defer_np.3, pthread_detach.3, pthread_equal.3, pthread_exit.3, pthread_join.3, pthread_kill.3, pthread_kill_other_threads_np.3, pthread_rwlockattr_setkind_np.3, pthread_self.3, pthread_setcancelstate.3, pthread_setconcurrency.3, pthread_setschedprio.3, pthread_testcancel.3, pthread_tryjoin_np.3, pthread_yield.3, puts.3, random.3, random_r.3, rpc.3, sched_getcpu.3, setnetgrent.3, sigwait.3, stdin.3, strerror.3, strfmon.3, timeradd.3, tmpnam.3, toupper.3, towlower.3, towupper.3, ttyname.3, uselocale.3, xdr.3, dsp56k.4, sigevent.7, vdso.7: ffix
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-15 17:26:11 +00:00
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.PP
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2016-04-21 11:07:01 +00:00
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.BI bswap_16( x );
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.BI bswap_32( x );
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.BI bswap_64( x );
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.fi
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.SH DESCRIPTION
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These macros return a value in which the order of the bytes
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in their 2-, 4-, or 8-byte arguments is reversed.
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.SH RETURN VALUE
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These macros return the value of their argument with the bytes reversed.
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.SH ERRORS
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These macros always succeed.
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.SH CONFORMING TO
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These macros are GNU extensions.
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.SH EXAMPLE
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The program below swaps the bytes of the 8-byte integer supplied as
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its command-line argument.
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The following shell session demonstrates the use of the program:
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.nf
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.in +4n
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$ \fB./a.out 0x0123456789abcdef\fP
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0x123456789abcdef ==> 0xefcdab8967452301
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.in
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.fi
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.SS Program source
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\&
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.nf
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#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <inttypes.h>
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#include <byteswap.h>
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int
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main(int argc, char *argv[])
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{
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uint64_t x;
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if (argc != 2) {
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fprintf(stderr, "Usage: %s <num>\\n", argv[0]);
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exit(EXIT_FAILURE);
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}
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x = strtoul(argv[1], NULL, 0);
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printf("0x%" PRIx64 " ==> 0x%" PRIx64 "\\n", x, bswap_64(x));
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exit(EXIT_SUCCESS);
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}
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.fi
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.SH SEE ALSO
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.BR byteorder (3),
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.BR endian (3)
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