如何在C中的extern函数中使用typedef？

Question

I have two modules written in C11 in my project: 'test1.c' and 'test2.c'. Module 'test1.c':

int FunctionWithVeryLONGLONGLONGLONGName(char* data)
{
    // do something
}

Module 'test2.c':

extern int FunctionWithVeryLONGLONGLONGLONGName(char* data);

int main(void)
{
    char data[ DATA_LEN + 1 ] = { "test_data" };
    FunctionWithVeryLONGLONGLONGLONGName(data);
    return 0;
}

I want to use short name for function 'FunctionWithVeryLONGLONGLONGLONGName' in module 'test2.c' without modification of module 'test1.c'. Fe, something like this:

FuncWithShortName(data);

I try to do:

extern int FunctionWithVeryLONGLONGLONGLONGName(char* data);
typedef int FunctionWithVeryLONGLONGLONGLONGName(char* data);
FunctionWithVeryLONGLONGLONGLONGName FuncWithShortName;

int main(void)
{
    char data[ DATA_LEN + 1 ] = { "test_data" };
    FuncWithShortName(data);
    return 0;
}

But compiler gave an error: "Definition of function FunctionWithVeryLONGLONGLONGLONGNamerequires parentheses." What did I do wrong ?

Answer 1

typedef creates a type alias, not a function alias or anything else.

You could get a sort of function alias by defining a file-local pointer to function:

static int (*const FuncWithShortName)(char*) =
    FuncWithVeryLONGLONGLONGLONGName;