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Directory and Search Path Preferences

This section describes the preferences for directories and search paths.

IDL_DIR

The IDL_DIR preference provides the value of the !DIR system variable, which contains the location of the IDL distribution that contains the currently running IDL program.

You cannot set IDL_DIR by using user or distribution preference files. The only valid sources for its value are the IDL command line, the IDL_DIR environment variable, or IDL's built-in default value (preferred when possible). The reason for this restriction is that the IDL distribution is an intrinsic part of the IDL program; it must be known before IDL starts running and is not something that can be changed afterwards.

The default value under UNIX is '/usr/local/itt/idl_xx', where xx represents the IDL version. The default value under Microsoft Windows is the location where the IDL installer wrote the IDL files on your system (typically C:\ITT\IDLxx, where xx represents the IDL version).

IDL_DLM_PATH

The IDL_DLM_PATH provides the value of the !DLM_PATH system variable, which contains the directories from which IDL loads dynamically loadable modules (DLMs).

Committed changes take effect in future IDL sessions. The default value is '<IDL_DEFAULT>', a special token which IDL replaces at startup with the correct set of directories from the IDL distribution for the currently running version of IDL. If you add directories to IDL_DLM_PATH, you should be careful to retain <IDL_DEFAULT> in your new value, or IDL will fail to find the provided DLM files. For example, you can use one of the following commands to add your own DLM directory. Under Windows:

PREF_SET, 'IDL_DLM_PATH', 'C:\your\path\here;<IDL_DEFAULT>', $  
   /COMMIT  

Under UNIX:

PREF_SET, 'IDL_DLM_PATH', '/your/path/here:<IDL_DEFAULT>', $  
   /COMMIT  

See EXPAND_PATH for more information on special syntax and <IDL_> tokens you can use in the path definition string. DLM files are IDL- and platform-specific. If you use DLMs with multiple versions of IDL, you might find the <IDL_BIN_DIRNAME> token of particular interest when setting up your DLM directories.

IDL_HELP_PATH

The IDL_HELP_PATH preference sets the value of the !HELP_PATH system variable, which determines the directories where IDL searches for online help files.

Committed changes take effect immediately. The default value is '<IDL_DEFAULT>', a special token which IDL replaces at startup with the correct set of directories from the IDL distribution for the currently running version of IDL. If you add directories to IDL_HELP_PATH, you should be careful to retain <IDL_DEFAULT> in your new value, or IDL will fail to find the provided help files. For example, you can use one of the following commands to add your own help directory. Under Windows:

PREF_SET, 'IDL_HELP_PATH', 'C:\your\path\here;<IDL_DEFAULT>', $  
   /COMMIT  

Under UNIX:

PREF_SET, 'IDL_HELP_PATH', '/your/path/here:<IDL_DEFAULT>', $  
   /COMMIT  

See EXPAND_PATH for more information on special syntax and <IDL_> tokens you can use in the path definition string.

IDL_MAKE_DLL_COMPILE_DIRECTORY

The IDL_MAKE_DLL_COMPILE_DIRECTORY preference sets the initial value of the !MAKE_DLL.COMPILE_DIRECTORY system variable, which specifies the location where the MAKE_DLL and CALL_EXTERNAL (with the AUTO_GLUE keyword set) routines do their work. A null string ('') for this preference specifies that IDL should create an appropriate platform-specific directory underneath the .idl subdirectory of the user's home directory. This default value is highly recommended because it automatically handles multi-platform issues.

Committed changes take effect at the next .reset_session executive command or in future IDL sessions. The default value is a null string ('').

IDL_PATH

The IDL_PATH preference provides the initial value of the !PATH system variable, which determines the directories that IDL searches for include files and programs written in the IDL language (.pro and .sav).'

Committed changes take effect immediately. The default value is '<IDL_DEFAULT>', a special token which IDL replaces at startup with the correct set of directories from the IDL distribution for the currently running version of IDL. If you add directories to IDL_PATH, you should be careful to retain <IDL_DEFAULT> in your new value, or IDL will fail to find the provided library files. For example, you can use one of the following commands to add your own library directory. Under Windows:

PREF_SET, 'IDL_PATH', 'C:\your\path\here;<IDL_DEFAULT>', $  
   /COMMIT  

Under UNIX:

PREF_SET, 'IDL_PATH', '/your/path/here:<IDL_DEFAULT>', $  
   /COMMIT  

See EXPAND_PATH for more information on special syntax and <IDL_> tokens you can use in the path definition string.


Note
You can set this preference in the IDLDE's Preferences dialog. For more information, see Search Path / IDL Files Search Path under Path Preferences.

IDL_PATH_CACHE_DISABLE

The IDL_PATH_CACHE_DISABLE preference determines whether or not the IDL path cache is enabled when IDL starts. For more information on the path cache, see PATH_CACHE.

Value
Aliases
0
False, No, Off
1
True, Yes, On

Committed changes take effect immediately. The default value is False (0), meaning that the cache is enabled.


Note
You can set this preference in the IDLDE's Preferences dialog. For more information, see Enable Path Cache under Path Preferences.

IDL_STARTUP

The IDL_STARTUP preference provides the path of a batch file that is executed automatically each time IDL is started and following a .reset_session or .full_reset_session executive command. (See Startup Files for more information on startup files.) A null string ('') indicates that there is no startup file.


Note
Startup files are only executed when running an application with a command line. See Understanding When Startup Files are Not Executed for details.

Committed changes take effect at the next .reset_session executive command or in future IDL sessions. The default value is a null string ('').


Note
You can set this preference in the IDLDE's Preferences dialog. For more information, see Startup File under Startup Preferences.

IDL_TMPDIR

The IDL_TMPDIR preference provides the location of a directory to be used for creating temporary scratch files, as returned by the GETENV function, if its value is non-null. If the value is a null string, GETENV instead returns the path of the standard directory used for this purpose by the current operating system.

Committed changes take effect immediately. The default value is a null string ('').

  IDL Online Help (March 06, 2007)