C typedef defined function

Question

Within C how can I name a function? Just the name.

typedef strlen StringLength fails to compile with: strlen does not name a type .

Answer 1

函数指针是一个解决方案

static Integer(*StringLength)(const Byte*) = strlen;

Answer 2

The correct way to "mock" a function - replacing the function call with another call - is to use #define . If you also don't want to worry about parameters, then simply do:

#define StringLength strlen

Function pointers might work too, but they may be restricted to a certain scope, and you must get the parameter and return types right. For strlen specifically, the correct type is (C11 7.24.6.3):

size_t strlen(const char *s);

Thus a correctly defined function pointer should look like:

size_t (*const StringLength) (const char*) = strlen;

Where the *const makes the function pointer itself read-only, which is good practice.