Commonly Used Environment Variables
This appendix describes some of the environment variables that are used with the QNX OS.
For general information about setting environment variables, see the
Configuring Your Environment
chapter of the QNX OS User's Guide;
for specific information, see the related utilities and programs.
In the table below, the where used
column indicates whether the variable is used on development hosts,
target systems running QNX OS, or both.
Variable | Where used | Description |
---|---|---|
COLUMNS | Target | The number of character columns on the screen. |
DISPLAY | Target | The name of the physical display on which to draw. |
DL_DEBUG | Target | If this environment variable is set, the
shared library loader displays debugging information about the libraries as they're opened.
The value can be a comma-separated list of the following:
A value of 1 (one) is the same as Note:
For security reasons, the runtime linker unsets DL_DEBUG if the binary has
the setuid bit set.
|
EDITOR | Target | The path of the editor you'd like to use by default. |
EXINIT | Target | Default elvis option settings. If set, the contents of this environment variable are executed on startup as a series of ex commands. |
GNUTARGET | Host | Specifies the target (output file format) for GNU utilities.
For more information, see the
Selecting the Target Systemappendix. |
GZIP | Target | A set of default options for gzip. |
HOME | Host, target | Your current working directory when you first log in. It's specified as one of the fields for each user in /etc/passwd. For more information, see passwd. |
HOSTALIASES | Target | The name of a file containing aliases for hosts. For more information, see getaddrinfo() in the C Library Reference (G page). |
HOSTNAME | Target | The name of the host machine. |
LANG | Target | The locale to use for the locale categories.
Note:
QNX OS currently supports only the POSIX (i.e., C) locale.
|
LC_TYPE | Target | The locale for character classification, used by
uniq
to determine the characters constituting a blank in the current locale.
Note:
QNX OS currently supports only the POSIX (i.e., C) locale.
|
LDEMULATION | Host | Specifies the linker emulation.
For more information, see the
Selecting the Target Systemappendix. |
LD_BIND_NOW | Target | Affects lazy-load dependencies due to full symbol resolution.
Typically, it forces the loading of all lazy-load dependencies (until all symbols have been resolved).
See
dlopen()
in the C Library Reference
and
Optimizing the runtime linkerin the Compiling and Debuggingchapter in the QNX OS Programmer's Guide. |
LD_DEBUG | Target | A synonym for DL_DEBUG.
If you set both DL_DEBUG and LD_DEBUG,
then DL_DEBUG takes precedence.
See
dlopen()
in the C Library Reference.
Note:
For security reasons, the runtime linker unsets LD_DEBUG if the binary has
the setuid bit set.
|
LD_DEBUG_OUTPUT | Target | The name of a file in which the runtime linker writes its output.
By default, output is written to stderr.
See
dlopen()
in the C Library Reference.
Note:
For security reasons, the runtime linker unsets LD_DEBUG_OUTPUT if the binary has
the setuid bit set.
|
LD_LIBRARY_PATH | Host, target | A colon-separated list of paths that the runtime linker uses to search for shared libraries.
See
dlopen()
in the C Library Reference
and the
Dynamic Linkingchapter in the System Architecture guide. Note:
For security reasons, the runtime linker unsets LD_LIBRARY_PATH if the binary has
the setuid bit set.
|
LD_PRELOAD | Host, target | A colon-separated list of full paths to the shared libraries on an ELF system that you
want to load before loading other libraries.
You can use this environment variable to add or change functionality when you run a program.
See
dlopen()
in the C Library Reference
and the
Dynamic Linkingchapter in the System Architecture guide. Note:
For security reasons, the runtime linker unsets LD_PRELOAD if the binary has
the setuid bit set.
|
LD_RUN_PATH | Host | A colon-separated list of the paths to search for shared libraries on an ELF system when linking, if you aren't using the -rpath option for ld. For more information, see the documentation for ld at https://www.gnu.org/software/binutils/. |
LD_TRAP_ON_ERROR | Target | If this environment variable is set, the runtime linker faults instead of exiting on fatal errors,
so that you can examine the core file that's generated.
See
Optimizing the runtime linkerin the Compiling and Debuggingchapter in the QNX OS Programmer's Guide. |
LESS | Target | Options that you want to pass to less automatically. |
LESSEDIT | Target | The editor prototype string (used for the v command in less). |
LIBC_FATAL_STDERR_ | Target | If this environment variable is both defined and non-empty, the message generated following the detection of a stack error in libc is written to standard error (stderr). Otherwise, the message is written to /dev/tty. |
LINES | Target | The number of character lines on the screen. |
LOCALDOMAIN | Target | The local domain name. For more information, see res_init() in the C Library Reference (R page). |
LOGNAME | Target | The userid you used to login; the same as USERNAME. |
MAKEFLAGS | Host | A set of default options for make. |
MALLOC_* | Target | These variables control how the memory allocator behaves;
some are supported by the normalallocator defined in libc, while some are supported by the librcheck version. For more information, see the entry for mallopt() in the C Library Reference. |
MKIFS_PATH | Host | A colon-separated list of directories that mkifs should use to search for host files to be included in an OS image. |
MORE | Target | Default options for more. |
PATH | Host, target | A colon-separated list of directories that are searched when the
shell looks for commands and . 'd files.
An empty string resulting from a leading or trailing colon or two adjacent
colons is treated as a . , the current directory.
For more information, see ksh. |
POSIX_STRICT | Target | If this environment variable is set, some utilities (e.g., cp, ls, and more) interpret options according to POSIX specifications. |
POSIXLY_CORRECT | Target | This environment variable is used by Unix-style operating systems to
alter behavior to comply with POSIX where it's different from the OS's default behavior.
POSIXLY_CORRECT is a de facto standard that isn't defined by POSIX.
If the POSIXLY_CORRECT environment variable is set:
|
PROC_THREAD_POOL | Target | The configuration of procnto's thread pool. |
PROCESSOR | Host | The target CPU type to use when building an image filesystem. For more information, see mkifs. |
QCC_CONF_PATH | Host | The name of the directory that contains the configuration files for qcc. |
QNX_CONFIGURATION | Host | The location of the configuration files for installations of QNX OS, version 6.6 or earlier. |
QNX_CONFIGURATION_EXCLUSIVE | Host |
The location of the configuration files for installations of QNX OS, version 7.0 or later. The default location is the $HOME/.qnx directory. You need to set this variable only if the default location isn’t accessible or if the configuration files are located on a build server. |
QNX_HOST | Host | The location of host-specific files for all development hosts. |
QNX_TARGET | Host | The location of target backends on the host machine. |
RESCONF | Target | An way of overriding configuration strings in the resolv.conf file. |
SHELL | Target | The pathname of the command interpreter, or shell, that you want to use. It's set by login. |
SIGKILL_TIMEOUT | Target | If this environment variable is defined, its value is used as the number of milliseconds that shutdown and shutdown_system() wait before sending a SIGKILL signal to processes that haven't yet terminated. |
STDIO_DEFAULT_BUFSIZE | Target | As a QNX OS extension to POSIX standard I/O, you can use this environment variable to override BUFSIZ as the default buffer size for stream I/O. The value of STDIO_DEFAULT_BUFSIZE must be greater than that of BUFSIZ. |
SYSNAME | Target | The name of the system. |
TERM | Target | The terminal type. |
TERMINFO | Target | The name of the directory for terminfo files; see tic. |
TMPDIR | Target | The name of a directory where utilities can create temporary files. |
TZ | Target | The timezone definition; see
Setting the time zonein the Configuring Your Environmentchapter of the QNX OS User's Guide. |
USER | Target | The userid you used to login; the same as LOGNAME. |