Which version of PCRE does Apache use for mod_rewrite?

Question

Several versions of PCRE are installed on my host.

phpinfo() shows that PHP uses version 8.21. In addition it shows a folder: "pcre-regex=/opt/pcre"

In the shell, when I run

/opt/pcre/bin/pcretest -C

the server shows more information for 8.21.

When I omit the directory and run

pcretest -C

the server shows information for PCRE 7.8.

What I'd like to know is which version of PCRE Apache uses for mod_rewrite.

which httpd returned "/usr/sbin/httpd", so I tried

ldd /usr/sbin/httpd | grep pcre

but that returned nothing.

Thanks in advance for any insights!

Answer 1

This may be something that's happening on your specific distribution or specific to your server's setup, but apache uses libpcre and should link to it (which should appear in ldd):

libpcre.so.1 => /lib/libpcre.so.1 (0xb780c000)

You may need to rely on your package manager to see what version of the package that file belongs to:

/lib/libpcre.so.1 -> libpcre.so.1.2.1

 * Searching for libpcre.so.1.2.1 ... 
dev-libs/libpcre-8.33 (/lib/libpcre.so.1.2.1)

It's also possible that you've got 2 pcretests installed, because it's sort of odd that you'd have system libraries in the /opt/ directory. It may be the place where some libraries end up getting installed in your distribution/setup. Debian's got a libpcre3 package which installs the library as /lib/libpcre.so.3.12.1 and the test as /usr/bin/pcretest. Ultimately it's going to depend on how httpd was build and what it expects to link to. What does simply ldd /usr/sbin/httpd say?

Answer 2

In the case of a cPanel install, which is my case, cPanel says that the version of PCRE installed by EasyApache is the one in the /opt folder.