## Environment variables

This section describes all environment variables that affect execution of wxWidgets programs.

`WXTRACE` | (Debug build only.) This variable can be set to a comma-separated list of trace masks used in wxLogTrace calls; wxLog::AddTraceMask is called for every mask in the list during wxWidgets initialization.

`WXPREFIX` | (Unix only.) Overrides installation prefix. Normally, the prefix is hard-coded and is the same as the value passed to `configure` via the `--prefix` switch when compiling the library (typically `/usr/local` or `/usr`). You can set WXPREFIX if you are for example distributing a binary version of an application and you don't know in advance where it will be installed.

`WXMODE` | (wxMGL only.) Sets MGL video mode. The value must be in form widthxheight-depth. The default is `640x480-16`.

`WXSTDERR` | (wxMGL only.) Redirects stderr output to a file.