The manual states above:
The default is to allow dynamic loading, except when using safe mode. In safe mode, it's always impossible to use dl().
...however, on the manual page for dl(), it states:
Note: dl() is not supported in multithreaded Web servers. Use the extensions statement in your php.ini when operating under such an environment. However, the CGI and CLI build are not affected !
Note: As of PHP 5, the dl() function is deprecated in every SAPI except CLI. Use Extension Loading Directives method instead.
Note: Since PHP 6 this function is disabled in all SAPIs, except CLI, CGI and embed.
Note: when magic_quotes_gpc is ON, it will also slash values inside both $_SERVER['QUERY_STRING'] and $_SERVER['SCRIPT_NAME'] (and equivalents) will also be slashed.
You probably don't want to set "magic_quotes_runtime" because it affects even binary file read/write operations. This is especially problematic if you include someone else's library that depends on binary read/write. If you enable "magic_quotes_runtime", be sure to use set_magic_quotes_runtime() function call to disable it before calling someone else's library that does binary read/write.