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when using php's mb_convert_case on an older production server, I get the following error:

Fatal error: Call to undefined function: mb_convert_case() in ...

So I checked and read mb string functions are not a default module. Printing my phpinfo() it returns php version 4.3.9 (php docs say mb string functions are available PHP 4 >= 4.3.0). In the very top of my phpinfo() I find the following string under "build command": '--enable-mbstring=shared'

As far as I can tell, this should mean mb string functions are installed, should it not? Why am I getting that error?

P.S.: The script as such runs fine on my local testing server/php version.

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Does your phpinfo() return any details about mb functions? I don't mean the --configure stanza but the module specific detail box down below. –  Janne Pikkarainen Jan 25 '12 at 14:15
Nope, none whatsoever except for the one mention at the very top. –  kontur Jan 25 '12 at 14:32
Does php.ini include a line like extension=mbstring.so? If mbstring was built shared then it was compiled into a separate library file (.so or .dll depending on platform), and that library file needs to be loaded in php.ini –  meulop Jan 27 '12 at 13:07
I am afraid I don't have access to the server's php.ini, but I given your comments, it would seem as if indeed the module was not loaded, would it not? Correct me if I am wrong, but I assume there is no way to load/activate that library from a php script? –  kontur Jan 27 '12 at 13:43
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