php startup error Invalid library (maybe not a PHP library) 'pcntl.so'

Question

After searching for hours to solve my problem and found nothing helpful I ask my first question here.

I want to compile and install php 5.3.17 cli with pcntl extension enabled on a Debian server. The installation was successfull but when I start php cli, the following error is displayed:

PHP Warning:  PHP Startup: Invalid library (maybe not a PHP library) 'pcntl.so' in Unknown\
on line 0

The following configure is used:

'./configure' '--prefix=/usr/share' '--datadir=/usr/share/php' '--bindir=/usr/bin' 
'--libdir=/usr/share' '--includedir=/usr/include' 
'--with-config-file-path=/etc/php5/cli' '--disable-cgi' '--enable-bcmath' 
'-- enable-inline-optimization' '--enable-mbstring' '--enable-mbregex' '--enable-pcntl'
'--enable-sigchild' '--enable-shmop' '--enable-sysvmsg' '--enable-sysvsem' 
'--enable-sysvshm' '--with-mysql' '--with-imap' '--with-imap-ssl' '--with-kerberos'

In the php.ini following options are set:

extension_dir=/usr/lib/php5/20090626/
extension=pcntl.so

I hope someone can help me.

Solution 1

I solved my problem now, with some help from this post stackoverflow answer how-to-enable-process-control-extension-pcntl-in-php-mamp.

First I switched to the source directory of the pcntl extension /src/php-5.3.17-cli/ext/pcntl.
There I ran the following commands in the shell:

phpize
./configure
make

Then the extension was created at /src/php-5.3.17-cli/ext/pcntl/modules and I copied it in the right directory with cp /src/php-5.3.17-cli/ext/pcntl/module/pcntl.so /usr/lib/php5/20090626/.

Now the extension works for my php-cli installation.
Thank you @terdon for your answer it pushed me a bit in the right direction.

Solution 2

You should have a file called pcntl.so in the modules subdirectory of the directory where you built php. Copy that to /usr/lib/php5/20090626/ :

sudo cp PHP_BUILD_DIR/modules/pcntl.so /usr/lib/php5/20090626/

Obviously, change PHP_BUILD_DIR to the directory where you compiled php.

Comments

[And-y]

After finishing the build of php the pcntl.so extension was created at /usr/share/extensions/no-debug-non-zts-20090626/ and I copied it to /usr/lib/php5/20090626/. When the pcntl.so file is not in the directory the following error message occurse: PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib/php5/20090626/pcntl.so' - usr/lib/php5/20090626/pcntl.so: cannot open shared object file: No such file or directory in Unknown on line 0 So I think the file is at the right place.