Questions about msubstr functions in thinkphp

The msubstr function in thinkphp defines common in the common file. php file, which defines function & nbsp; msubstr () & nbsp ;{} and passes the local test completely. However, when you put it on Sina SAEs, the following error occurs: Call & nbsp; to & nbsp; undefined & nbsp; msubstr function in fun thinkphp
The common. php file is defined in the common file, which defines
Function msubstr (){

}
In addition, the local test is completely successful, but an error is prompted during access when it is placed on Sina sae:
Call to undefined function msubstr ()......
Error location
FILE:/data1/www/**********/ThinkPHP/Extend/Engine/Cluster/Lib/Core/Think. class. php LINE: 284

So helpless...
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Remove the semicolon in the php configuration file
Extension = php_mbstring.dll
Make sure that the mbstring module is loaded.
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I have encountered the same situation as the landlord. it is useless to put the common in the common folder of the project. I can put the common in the thinkPHP framework later. The specific reason is not detailed...
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Try another method name
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Consider THINKPHP cache files.