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uac(1) [ultrix man page]

uac(1)							      General Commands Manual							    uac(1)

Name
       uac - Unaligned Access Message Control

Syntax
       uac [s] [p] value

Description
       The  command  controls  the  printing of "Fixed up unaligned data access for pid nnn at pc 0xAddr" messages.  The command is used to set or
       display the flag that controls printing the message for the system or for the parent process of the user, which is typically a shell.

       If value is present, the flag is set; otherwise, the current flag setting is displayed.	The value can be either a zero	(0),  which  turns
       the  flag  off,	or  a  one  (1), which turns the flag on.  If both the system and the user flags are on (set, 1) the unaligned data access
       errors are reported to the user.  If either flag is off (not set, 0), the unaligned data access errors are not reported.

Options
       The following options can be used with the command:

       s    Set/display the current flag setting for the system.

       p    Set/display the current flag setting for the parent process.

Restrictions
       You must be superuser to set the system flag.

								       RISC								    uac(1)

Check Out this Related Man Page

PRCTL(1)						      General Commands Manual							  PRCTL(1)

NAME
prctl - Process operations SYNOPSIS
prctl [-v] [-h|--help] [--version] <-q|<options....>> [command] where <options> are: --unaligned=[silent|signal|default] --fpemu=[silent|signal|default] DESCRIPTION
prctl allows you to query or control certain process behavior. Supported options are handling of unaligned memory accesses and floating point assistance faults by a process. When a process performs an unaligned memory access, by default the kernel would emulate the unaligned access correctly and log the unaligned access in syslog. This behavior can be changed so the kernel could either emulate the unaligned access correctly without logging an error or send SIGBUS to the process. Similarly when a process encounters a floating point assist fault, kernel would invoke floating point emulator and log the floating point assist fault. This behavior can be changed so the ker- nel could either emulate floating point operation without logging an error or send SIGFPE to the offending process. prctl can optionally be followed by a command. If a command is specified, prctl will exec the command with the processor behavior set to as specified by the options. If a command is not specified, prctl will fork a new shell unless the command only queried the current settings. The shell started by prctl will be as defined by the environment variable SHELL. If environment variable SHELL is not defined, shell in the password entry for the user will be started. If a shell is not found in the password entry, bash will be started. OPTIONS -v Verbose mode. In verbose mode, any new settings are confirmed with a message on stdout. --help Print usage information and exit. --version Print software version and exit. -q Query the current settings for the process options controllable by prctl. --unaligned=[silent|signal|default]] Set unaligned memory access behavior to not log the access (silent), send SIGBUS to the process (signal), or do the default (default). If a value is not specified after "=", current setting is returned. --fpemu=[silent|signal|default]] Set floating point assist fault behavior to not log the faulti (silent), send SIGFPE to the process (signal), or do the default (default). If a value is not specified after "=", current setting is returned. If an option is specified multiple times, the last one takes effect. EXAMPLES
prctl --unaligned=signal starts up a shell (as defined by the environment variable SHELL) and sets up any process running under this shell to be sent SIGBUS upon an unaligned memory access. prctl --unaligned=signal gdb tst starts up a gdb session for the program "tst" with the process set to receive SIGBUS upon unligned memory access. prctl --unaligned= displays the current setting for unaligned memory access handling. prctl --unaligned= gdb tst displays the current setting for unaligned memory access handling and starts up a gdb session for the program "tst". NOTES
prctl works on 2.4.0 and above kernels only. --fpemu= option is specific to IPF (Itanium Processor Family, previously known as IA-64) and is supported on kernels 2.4.11 and above. Other architectures and kernels may return "Invalid argument" error. prctl(2) AUTHOR
Khalid Aziz <khalid_aziz@hp.com> LICENSE
This software is made available under the GNU General Public License (GPL) Version 2. This software comes with NO WARRANTY. Process operations PRCTL(1)
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