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The red part is my annotation.
For more information, see:

1. Commonly used general functions have been encapsulated in header files such as zen_API.h, so there is no need to look at internal details and waste time. (Reference: Appendix A of Extending and Embedding PHP)
2. Run the test program in the terminal and you can see the internal error output of the extension. This is especially important for solving memory leak problems. (Compile a debug lib)
3. During the development process, modify "CFLAGS = -g -O2" in the Makefile, remove the optimization options, and add -Wall and -pedantic to facilitate debugging and display compilation warnings;
4 .For a certain zval*, but its strval is not copied, zval_ptr_dtor(zval**) cannot be used, efree(void*) must be used.
5. $_SERVER['PWD'] in terminal has a value, but it cannot be obtained through zend_getenv(). The reason should be that the value is meaningless or unreliable.
6. When calling the "exported function", you can use INTERNAL_FUNCTION_PARAM_PASSTHRU to pass parameters; the declared non-exported function can use the parameters of the "exported function" through INTERNAL_FUNCTION_PARAM.
7. Note: When RETURN_TYPE is used to select the sum of divisions loop, etc., it is best to place it in curly braces,
or without a semicolon, because: #define RETURN_BOOL(b) { RETVAL_BOOL(b); return ; }.
8. If the parameters of the function are references and non-scalar, they must be destructed first to prevent memory leaks.
9. Before throwing an exception, it is best to determine whether there is already an exception in EG (exception), otherwise it will cause a memory leak.
10. When the Web server API is ISAPI (IIS), the zend_getenv function does not work.
11. Pass in the data pointer to zend_stack_push(). What is actually stored (copied) is the data pointed to by the pointer. In other words, what is passed in should be the pointer of the data to be stored.
ZEND_API int zend_stack_push(zend_stack *stack, void *element, int size);
ZEND_API int zend_stack_top(zend_stack *stack, void **element);
Where, size == sizeof(*element);
Similarly, the same is true for zend_hash, compare zend_hash_update and zend_hash_find.
12. Use add_assoc_zval(HashTable*, const char*, zval*) to store zval* instead of zval. Therefore,
When storing the parameters passed in by the user, you must first copy a new zval. Otherwise unpredictable things may happen.
13.zval_dtor(zval*) releases the variable and its internal reference memory. zval_ptr_dtor(zval**) first checks the refcount
before deciding whether to call zval_dtor(zval*). zval_copy_dtor(zval*) only performs deep Copy, that is, only copy the memory referenced internally by
, but not the zval;

14. If you use VC to compile the win dynamic link library, and the zend function, such as zend_getenv, is called in the code, in zend .h is defined as:



extern "C" {
extern ZEND_API char *(*zend_getenv)(char *name, size_t name_len TSRMLS_DC);
}
This function needs to be introduced. If you want to use ZEND_API, you need to cancel LIBZEND_EXPORTS (including the preprocessing definition in VC "Settings") in advance, or use ZEND_DLIMPORT,
ZEND_DLIMPORT char *(*zend_getenv)(char *name, size_t name_len TSRMLS_DC ; 🎜># define ZEND_API __declspec(dllexport)
#else
# define ZEND_API __declspec(dllimport)

#endif #define ZEND_DLEXPORT __declspec(dllexport) #define ZEND_DLIMPORT __declspec(dllimport)

executor_globals_id also needs to be declared as follows:

ZEND_DLIMPORT int executor_globals_id;
(This is more useful if you want to manually compile certain extensions, such as when I compile the sqlite3 extension , encountered this problem).



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The red part is my comment. For more information, see: 1. Commonly used general functions have been encapsulated in header files such as zen_API.h, so there is no need to look at internal details and waste time. (Reference...