php-memory-profiler: Dump file not being generated and missing function

I’ve installed memprof via pecl on macos on php 7.2, pecl installed memprof 2.1.2

I’ve run a quick test with:

<?php

var_dump(memprof_enabled());
memprof_dump_callgrind(fopen("output", "w"));
$arr = [];
while (true) {
    array_push($arr, 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa');
}

memprof_enabled() works and is true, I also get the output generated by memprof_dump_callgrind however:

• trying to call var_dump(memprof_enabled_flags()); gives Call to undefined function memprof_enabled_flags()
• calling the above script with MEMPROF_PROFILE=dump_on_limit php test.php doesn’t output the dump on crash

I’ve tried to also change the dump folder to put it in the current working directory, no output

Any idea?