Options for PHP Regular Expressions

Regular expressions can have options (also known as flags) that modify their behavior. Each engine supports a different set of options.

Option	Description	Backend value	Portable value
i	PCRE_CASELESS	ignorecase	ignorecase
m	PCRE_MULTILINE	multiline	multiline
s	PCRE_DOTALL	dotall	dotall
x	PCRE_EXTENDED	comment	comments
u	PCRE8	unicode	(not portable)