# Installation

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parallel requires a build of PHP with ZTS (Zend Thread Safety) enabled (`--enable-zts`, or on non-Windows systems prior to PHP 8.0.0, `--enable-maintainer-zts`)

Zend Thread Safety cannot be enabled post build; it is a build time configuration option.

parallel should build anywhere there is a working Posix Threads header (pthread.h) and ZTS build of PHP, including Windows (using the pthread-w32 project from redhat).

&reftitle.install;

parallel releases are hosted by PECL and the source code by github, the easiest route to installation is the normal PECL route: &url.pecl.package;parallel.

Windows users can download prebuilt release binaries from the PECL website.

Windows users need to take the additional step of adding pthreadVC2.dll (distributed with Windows releases) to their `PATH`.