C++ in C application

In this example, an imaginary fancy library written in C++ is linked with a C application. There are a few things to be done:

• the header fancy_lib/fancy.h needs to be C-compatible,

• the functions declarations and definitions must be wrapped with extern "C" to ensure C-style linkage:

  #ifdef __cplusplus
  extern "C" {
  #endif
  
  void fancy_function(int a);
  
  #ifdef __cplusplus
  }
  #endif

Example

To setup and build project, then run example do:

cmake -S . -B build
cmake --build build --parallel
cmake --build build --target run-example

Note

Here CMake by default will use C++ compiler for example, so set_target_properties was used to set C compiler and linker.

Link library manually

When not using CMake and linking library manually the C++ library must be linked explicitly:

gcc -Ifancy_lib example/example.c -Lbuild/fancy_lib -lfancy -lstdc++