How do I enable --enable-soap in php on linux?

Getting SOAP working usually does not require compiling PHP from source. I would recommend trying that only as a last option.

For good measure, check to see what your phpinfo says, if anything, about SOAP extensions:

$ php -i | grep -i soap

to ensure that it is the PHP extension that is missing.

Assuming you do not see anything about SOAP in the phpinfo, see what PHP SOAP packages might be available to you.

In Ubuntu/Debian you can search with:

$ apt-cache search php | grep -i soap

or in RHEL/Fedora you can search with:

$ yum search php | grep -i soap

There are usually two PHP SOAP packages available to you, usually php-soap and php-nusoap. php-soap is typically what you get with configuring PHP with --enable-soap.

In Ubuntu/Debian you can install with:

$ sudo apt-get install php-soap

Or in RHEL/Fedora you can install with:

$ sudo yum install php-soap

After the installation, you might need to place an ini file and restart Apache.

In case that you have Ubuntu in your machine, the following steps will help you:

1. Check first in your php testing file if you have soap (client / server)or not by using phpinfo(); and check results in the browser.In case that you have it, it will seems like the following image ( If not go to step 2 ):

2. Open your terminal and paste: sudo apt-get install php-soap.

3. Restart your apache2 server in terminal : service apache2 restart.

4. To check use your php test file again to be seems like mine in step 1.

As far as your question goes: no, if activating from .ini is not enough and you can't upgrade PHP, there's not much you can do. Some modules, but not all, can be added without recompilation (zypper install php5-soap, yum install php-soap). If it is not enough, try installing some PEAR class for interpreted SOAP support (NuSOAP, etc.).

In general, the double-dash --switches are designed to be used when recompiling PHP from scratch.

You would download the PHP source package (as a compressed .tgz tarball, say), expand it somewhere and then, e.g. under Linux, run the configure script

./configure --prefix ...

The configure command used by your PHP may be shown with phpinfo(). Repeating it identical should give you an exact copy of the PHP you now have installed. Adding --enable-soap will then enable SOAP in addition to everything else.

That said, if you aren't familiar with PHP recompilation, don't do it. It also requires several ancillary libraries that you might, or might not, have available - freetype, gd, libjpeg, XML, expat, and so on and so forth (it's not enough they are installed; they must be a developer version, i.e. with headers and so on; in most distributions, having libjpeg installed might not be enough, and you might need libjpeg-dev also).

I have to keep a separate virtual machine with everything installed for my recompilation purposes.