Stubbing a C function that has a a parameter with the same name in C++

Question

 int stat(const char *__restrict__ __file, struct stat *__restrict__ __buf); 

This function needs to be stubbed in order to cover more branches in an unit test made using Google Unit Test.

In file stubs.h

I have to stub this function, so I provide the following prototype:

int stat_stub(const char *__restrict__ __file, struct stat *__restrict__ __buf);

Followed by:

#define stat stat_stub
int stat_RET;

Implementation in stubs.c

int stat_stub(const char *__restrict__ __file, struct stat *__restrict__ __buf)
{
    return stat_RET;
}

The problem is that the define also replaces struct stat with struct stat_stub , and this causes a multitude of errors to appear when compiling.

I would like to know if there is a workaround to this issue, as I am currently stuck on it.

Answer 1

您可以使用带参数的宏。

#define stat(p1,p2) stat_stub(p1,p2)

Answer 2

You don't have to use macros at all, instead you can make it differ in build system.

---

Remove stubs.h and only use real header in production code.

In stubs.c define function with the same name:

int stat(const char *__restrict__ __file, struct stat *__restrict__ __buf)
{
    return stat_RET;
}

Now, when building production target, you link real implementation. For UT target, you build and link stubs.c .

This solution will be more versatile than macros and easier to maintain.

Answer 3

The root of all your problems is that you name types and functions the same thing. Simply don't do that, unless this is a C++ constructor. It doesn't look like one. The only reason this code compiles in C, is because C uses different namespaces for struct tags and function identifiers.

The solution to all your problems is not to use macros or other work-arounds, but to implement a coding standard for how you name types and functions.