PR_SET_UNALIGN(2const)

PR_SET_UNALIGN2const

Set unaligned access control bits

Usage

#include <linux/prctl.h>  /* Definition of PR_* constants */
#include <sys/prctl.h>

int prctl(PR_SET_UNALIGN, unsigned long flag);

Library

Standard C library (libc, -lc)

Overview

Set unaligned access control bits to arg2.

Pass PR_UNALIGN_NOPRINT to silently fix up unaligned user accesses, or PR_UNALIGN_SIGBUS to generate SIGBUS on unaligned user access.

Alpha also supports an additional flag with the value of 4 and no corresponding named constant, which instructs kernel to not fix up unaligned accesses (it is analogous to providing the UAC_NOFIX flag in SSI_NVPAIRS operation of the setsysinfo() system call on Tru64).

Return value

On success, 0 is returned. On error, -1 is returned, and errno is set to indicate the error.

Errors

EINVAL

flag is not a valid value.

Releases

2 releases since Debian 13 (Trixie); the text changed 1 time.

  1. 13
  2. Arch

Standards

Linux.

History

Only on:

•

ia64, since Linux 2.3.48

•

parisc, since Linux 2.6.15

•

PowerPC, since Linux 2.6.18

•

Alpha, since Linux 2.6.22

•

sh, since Linux 2.6.34

•

tile, since Linux 3.12

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