The behaviour of these functions is affected by settings in php.ini.
Table 1. Misc. Configuration Options
Here's a short explanation of the configuration directives.
TRUE by default. If changed to FALSE scripts will be terminated as soon as they try to output something after a client has aborted their connection.
See also ignore_user_abort().
Colors for Syntax Highlighting mode. Anything that's acceptable in <font color="??????"> would work.
Name (e.g.: browscap.ini) and location of browser capabilities file. See also get_browser().