4.6 The Scope of mod_perl Configuration Directives
Table 4-1 depicts where the various mod_perl configuration directives can be used.
The first column represents directives that can appear in the global configuration; that is, outside all sections. Note that PerlTaintCheck, PerlWarn, and PerlFreshRestart can be placed inside <VirtualHost> sections. However, because there's only one Perl interpreter for all virtual hosts and the main server, setting any of these values in one virtual host affects all other servers. Therefore, it's probably a good idea to think of these variables as being allowed only in the global configuration.
The second column represents directives that can appear inside the <VirtualHost> sections.
The third column represents directives that can appear in the <Directory>, <Location>, and <Files> sections and all their regex variants. These mod_perl directives can also appear in .htaccess files.
For example, PerlWarn cannot be used in <Directory> and <VirtualHost> sections. However, PerlSetEnv can be used anywhere, which allows you to provide different behavior in different sections:
PerlSetEnv ADMIN_EMAIL firstname.lastname@example.org <Location /bar/manage/> PerlSetEnv ADMIN_EMAIL email@example.com </Location>
In this example, a handler invoked from /bar/manage/ will see the ADMIN_EMAIL environment variable as firstname.lastname@example.org, while other handlers configured elsewhere will see ADMIN_EMAIL as the default value, email@example.com.