Problem with function redefinition when extending PHP with C++

Question: When I used C++ to extend php, I used some mathematical library functions such as sqr, sqrt, etc. I need to #include in the source file test.cpp of the C++ extension project, but these functions were found during compilation. There is a problem of redefinition.

After many attempts, I found that when #include "php.h" at the beginning of test.cpp is removed, this problem disappears

Reason: From the query, many C++ library functions are included in php.h Inline is defined directly in php.h, causing the function definition of the same name in the C++ library function file stdio.h to be recognized as a redefinition (inline-modified functions are not allowed to be defined in other files)

Solution: There will be redefined functions The C++ header file #include is written before #include "php.h" to block the inline function. Its location in test.cpp is as follows:

#ifdef HAVE_CONFIG_H #include "config.h" #endif #include  #include  #include  #include  #include "php.h" #include "php_ini.h" #include "ext/standard/info.h" #include "php_NearestNeighbors.h"