The preg_last_error() function returns an error code for the most recently evaluated regular expression. The returned value will match one of the following constants:
| Constant | Description |
|---|---|
| PREG_NO_ERROR | No error occurred |
| PREG_INTERNAL_ERROR | There was an error evaluating the expression |
| PREG_BACKTRACK_LIMIT_ERROR | The number of backtracks needed to evaluate the expression exceeded the limit given in PHP's configuration |
| PREG_RECURSION_LIMIT_ERROR | The recursion depth needed to evaluate the expression exceeded the limit given in PHP's configuration |
| PREG_BAD_UTF8_ERROR | The input string contained invalid UTF-8 data |
| PREG_BAD_UTF8_OFFSET_ERROR | During evaluation, a string offset did not point to the first character of a multibyte UTF-8 symbol |
| PREG_JIT_STACKLIMIT_ERROR | The JIT compiler ran out of stack memory when trying to evaluate the expression |