3v4l.org

run code in 300+ PHP versions simultaneously
<?php var_dump(strtoupper(NULL));
Output for 8.1.0 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
Deprecated: strtoupper(): Passing null to parameter #1 ($string) of type string is deprecated in /in/B3qIp on line 2 string(0) ""
Output for 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.34, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30
string(0) ""

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272.21 ms | 403 KiB | 381 Q