（ZeroMQ安装失败）zmq.so：未定义的符号：zend_new_interned_string

Question

I tried to install ZMQ for PHP recently and ran into the following problem:

apache2: Syntax error on line 137 of /etc/apache2/httpd.conf: Cannot load modules/extra_zmq.so into server: /usr/lib64/apache2/modules/extra_zmq.so: undefined symbol: zend_new_interned_string

• I followed the steps to install 0mq and everything went fine: http://www.zeromq.org/intro:get-the-software
• I ran needed commands to make php-zmq: http://zeromq.org/bindings:php
• Just to be sure I configured with php config set: phpize && ./configure --with-php-config=/usr/bin/php-config

make test on php-zmq shows my PHP version is used (7.1.11, along with Zend 3.1.0) and fail for these two tests (don't know if it's related, I couldn't find more information about these tests):

FAILED TEST SUMMARY
---------------------------------------------------------------------
Test adding / removing items [tests/007-addremovepoll.phpt]
Test callback edge-cases [tests/019-callbackinvalidsignature.phpt]

I tried downloading from both Github and PECL repository without any luck.

Answer 1

Well I found the problem, the extension was meant to be loaded by PHP and not by Apache. I was trying to use LoadModule (a2enmod) in httpd.conf, but this extension needs to be used with PHP, with the proper directive: extension=zmq.so.