This extension requires the c-client library to be installed. Grab the latest version from » https://github.com/uw-imap/imap and compile it.
It's important that you do not copy the IMAP source files directly into the system include directory as there may be conflicts. Instead, create a new directory inside the system include directory, such as /usr/local/imap-2000b/ (location and name depend on your setup and IMAP version), and inside this new directory create additional directories named lib/ and include/. From the c-client directory from your IMAP source tree, copy all the *.h files into include/ and all the *.c files into lib/. Additionally when you compiled IMAP, a file named c-client.a was created. Also put this in the lib/ directory but rename it as libc-client.a.
Note:
To build the c-client library with SSL or/and Kerberos support read the docs supplied with the package.
Note: In Mandrake Linux, the IMAP library (libc-client.a) is compiled without Kerberos support. A separate version with SSL (client-PHP4.a) is installed. The library must be recompiled in order to add Kerberos support.
For those using Ubuntu and who are completely daunted by compiling this, it's easy under Ubuntu:Install libc-client-dev# sudo apt-get install libc-client-devInstall PHP5 imap:# sudo apt-get install php5-imapRestart Apache# sudo service apache2 reloadShould work for most people.It should be noted that the source code archives at the University of Washington, and the mirrors, have been dead for some time.There is a github repository located here: https://github.com/uw-imap/imapphp-imap package is not available neither in Red Hat Enterprise Linux 7 nor 8.To compile the extension yourself:Prerequisites# yum install pam-devel openssl-develFollow steps 2 and 3 from the previous post of "ldi at email dot cz"Download the c-client library from github, you can see the link at the top of the page and compile with:# make lr5 SSLINCLUDE=/usr/include/openssl/ EXTRACFLAGS=-fPIC(if you are using another distro, instead of lr5 you will type something else, you can view the Makefile for other unix flavors)Follow step 5 from the previous post of "ldi at email dot cz" which is what the second paragraph at the top of the page explains.Download the PHP source code of the version installed in your system and go to the php/ext/imap folder.# phpize(If you installed the PHP packages from the Red Hat Software Collections you must run the following command before to set the enviroment eg: scl enable rh-php73 bash)# ./configure --with-imap=<<path_to_where_you_unpacked_the_c-client_library_and_compiled_it>> --with-imap-ssl# makeThis creates the file php/ext/imap/modules/imap.so :)Copy it to your extension_dir (you can find it in the phpinfo() page).Create an .ini file in the php.d folder with the text: extension=imap.soRestart apache and be happy.P.S. You could probably find the extension compiled out there but who knows the trustiness of the source so better to get the official unaltered sources.The Alpine email client which was also originally developed by Mark Crispin at UW also uses the "c-client" library and that it is still actively developed by Eduardo Chappa: https://alpineapp.email/alpine/release/ . It has its own updated copy of the "c-client" library which supports new features like OAuth2 authentication, etc.The development of the UW IMAP and Alpine "c-client" libraries can be compared via https://github.com/uw-imap/imap/commits/master/src/c-client and https://repo.or.cz/alpine.git/history/HEAD:/imap/src/c-clientIf this PHP extension does not work with Alpine "c-client", it might behoove someone to port the PHP so it does.