How to solve Preg_match warning? [duplicate]

问题

This question already has answers here:

PHP regular expressions: No ending delimiter '^' found in (3 answers)

Closed 5 years ago.

I am using preg_match function in my program. The code is like this

if (!$this->config_allow_src_above_docroot && !preg_match('^'.preg_quote(str_replace(DIRECTORY_SEPARATOR, '/', realpath($this->config_document_root))), $AbsoluteFilename))

But run the application it shows the warning like this

Warning: preg_match() [function.preg-match]: No ending delimiter '^' 

Can you help me please..

回答1:

You must add pattern delimiters:

preg_match('/^' . preg_quote(str_replace(DIRECTORY_SEPARATOR, '/', realpath($this->config_document_root))) . '/', $AbsoluteFilename)
            ^                                                                                                 ^

Since you have forgotten to put delimiters in your pattern, the regex engine believes that ^ is the starting delimiter and is surprised to not found the same delimiter at the end of the pattern.

来源：https://stackoverflow.com/questions/21339492/how-to-solve-preg-match-warning