20.3 Environment Variables Recognized by texi2any

makeinfo also reads the environment variable TEXINFO_OUTPUT_FORMAT to determine the output format, if not overridden by a command line option. The value should be one of:

docbook  dvi  dvipdf  html  info  pdf  plaintext  ps  xml

If not set or otherwise specified, Info output is the default.

The customization variable of the same name is also read; if set, that overrides an environment variable setting, but not a command-line option. See Customization Variables and Options.

You can control texi2any’s use of Perl extension modules by setting the TEXINFO_XS environment variable. These modules are compiled native code that the interpreted Perl code can use. Ideally, these extension modules should just work, and the only noticable difference they should make is that texi2any finishes running sooner. However, you can use this environment variable for the purposes of troubleshooting: for example, if you have problems with the output of texi2any varying depending on whether the extension modules are in use.

The following values of TEXINFO_XS are recognized by texi2any:

‘default’

The default behavior. Try to load extension modules, and silently fall back to the interpreted Perl implementations if this fails.

‘warn’

Try to load extension modules, and if this fails, give a warning message before falling back to the interpreted Perl implementations.

‘debug’

Try to load extension modules, printing many messages while doing so.

‘omit’

Do not use extension modules.

Set TEXINFO_XS_PARSER to ‘1’ to enable the use of the native code implementation of the parser module. This is the part of texi2any that converts Texinfo input into an internal tree format used for further processing into output formats. This is not enabled by default due to the greater complexity of this module compared with the other modules that have a native code implementation, and the lack of confidence we have that the native code implementation matches the Perl code in all significant aspects. Despite the lack of maturity of this module in terms of development and testing, it may be useful for decreasing texi2any run times when working on Texinfo documentation files. Note that some error and warning messages will not be translated from English if this module is used.