Undefined Reference error when linking c function in c++

Post Date: 2018-12-04

Please noted that C and C++ are different languages. Their compiler will create different symbol names on object. So C++ linker cannot find the correct symbol which is compiled by C compiler.

If you want to link the C function in C++, you have to define the function with extern "C" block. Here is the example:

#ifdef __cplusplus
extern "C" {
#endif

	void printhex(const unsigned char *buf, size_t n);

#ifdef __cplusplus
}
#endif

References:

• Linking static C library with C++ code