In the C language, how to use static function of non-current file?

Question

fileA.c has a static function (static int funcA())

The fileA.c can not be modified.

fileB.c How can I use the funcA()?

Answer 1

In general you cannot, that's the entire point of static in this case.

Perhaps fileA.c has a way to get the address of the function, then you can use that to make a call, but you can't reference static symbols directly.

For test code, one "trick" that's often done is to #include the C file in the test file, so in fileA_test.c you'd have:

#include "fileA.c"

bool test_fileA_something(void)
{
  TEST_ASSERT(foo() == 42);
}

The above assumes that foo is a static function inside fileA.c, and this works since the files are compiled together.

Answer 2

Not. The compiler has every right to not include funcA in fileA.obj. And even if it is included, it might not be in a form that the linker can use. In fact, if included it must be in a way that doesn't clash with other functions names funcA