Description:
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Posix has a function called strsignal(), since at least POSIX.1-2008, docs can be found here https://pubs.opengroup.org/onlinepubs/9699919799/functions/strsignal.html 

but the TL;DR is that it converts a signal to it's signal name (like in Linux, signal 15 is SIGTERM, and it converts int(15) to string("SIGTERM"))

would be nice if the posix extension could add support for it.


a naive-ish userland implementation can be found at https://stackoverflow.com/a/58471626/1067003
 (i don't know if the userland implementation is error-free, and it does not use the posix strsignal() function, but at least it appears to work)

Test script:
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<?php

var_dump(posix_strsignal(SIGTERM));

Expected result:
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string(7) "SIGTERM"

Actual result:
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PHP Fatal error:  Uncaught Error: Call to undefined function posix_strsignal() in /foo.php:3
Stack trace:
#0 {main}
  thrown in /jail/home/foo.php on line 3