ereg() / eregi() — POSIX Regex Removed in PHP 7

TL;DR

Explanation

ereg() and eregi() (case-insensitive) used POSIX Extended Regular Expressions. Deprecated in PHP 5.3, removed in PHP 7.0. PCRE (Perl-Compatible Regular Expressions) via preg_match() is faster and far more capable. Migration: ereg('pattern', $string, $matches) → preg_match('/pattern/', $string, $matches). Delimiters required in preg_match. eregi → preg_match with /i flag. ereg_replace → preg_replace. split → preg_split. Rector handles this migration automatically.

Common Misconception

Why It Matters

Common Mistakes

• Not running Rector to auto-migrate ereg to preg_match.
• Direct translation missing delimiters: ereg('foo') → preg_match('foo') — wrong, needs /foo/.
• Forgetting eregi → preg_match with /i flag.

Code Examples

if (ereg('^[a-z]+$', $input)) { } // Fatal in PHP 7+
eregi('[0-9]', $string); // Case-insensitive digit check

if (preg_match('/^[a-z]+$/i', $input)) { } // PCRE
if (preg_match('/[0-9]/', $string)) { } // Digits

References

• ↗ https://www.php.net/manual/en/migration70.removed-exts-sapis.php

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