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<?php $a = []; $mem = mem_get_real_usage(true); echo $mem; $c = new \stdClass(); $a[] = $c; echo mem_get_real_usage(true) - $mem; $a[] = $c; echo mem_get_real_usage(true) - $mem;
Output for 7.0.0 - 7.0.20, 7.1.0 - 7.1.25, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
Fatal error: Uncaught Error: Call to undefined function mem_get_real_usage() in /in/aIvnc:5 Stack trace: #0 {main} thrown in /in/aIvnc on line 5
Process exited with code 255.
Output for 5.5.24 - 5.5.35, 5.6.8 - 5.6.28
Fatal error: Call to undefined function mem_get_real_usage() in /in/aIvnc on line 5
Process exited with code 255.

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