Owing to changes in recent perls (5.8+ I believe), signals no longer interrupt a single opcode's execution. A regex is a single opcode, so the alarm never interrupts it. One solution, as mentioned above, is to use unsafe signals, although I am unsure if it is merely an ENV variable or a compile option. As the name says, these are potentially unsafe as a signal may interrupt an opcode that isn't interruptible and thus crash perl, but this is a very rare case.

Your other option involves using the Regexp::Parser to create a new regex that has embedded time checking functionality (by inserting (?{}) blocks) or by forking a seperate process and using various means (rlimits, etc) to control the length of execution of the process

Note that running user defined regexes is HORRIBLY UNSAFE as the user may embed any perl code he wishes in the regex.

In reply to Re: Losing control of large regular expressions by BUU
in thread Losing control of large regular expressions by scottb

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