The extension is not thread safe

[cmb69]

Since mbuf is a true global variable

php-md4c/md4c.c

Line 75 in 5f94bd5

static struct membuffer mbuf = { NULL, 0, 0 };

the extension is not suitable for running with Zend Thread-Safety (ZTS) builds of PHP. See https://www.phpinternalsbook.com/php7/extensions_design/globals_management.html#managing-request-globals for some details.

[eklausme]

Thanks for comment.

Followed the advice given in above link.

[cmb69]

Thank you! I found a minor issue (see #6), but otherwise it works. :)

[eklausme]

Thanks a lot Christoph for helping out!