Best practice to link modules split into multiple files with gcc/g-CodePudding

I would like to have a file containing only the declarations in a module and one or more files containing the definitions.

According to How to split a module into multiple files (and this awseome cppcon talk: https://youtu.be/nP8QcvPpGeM at 12:04) I should split my files like this:

Log.cpp:

export module Log;

int i = 0;
export void Log();

Log_imp.cpp:

module Log;

void Log() {
    std::cerr << "This is a log and i=" << i << "\n";
}

I can build both with g -11 -std=c 20 -fmodules-ts -c Log.cpp and g -11 -std=c 20 -fmodules-ts -c Log_imp.cpp respectively.

My main simply imports the Log module and calls the Log() function. Note that I have to link with both Log.o and Log_imp.o, otherwise I get linking errors.

Is it possible to have a single object file for a single module, without building a static library? If not, then should I link modules into a static library, or keep multiple .o files?

CodePudding user response：

Modules are basically orthogonal to the linking process. Each module file is its own translation unit and therefore will produce its own object file. You can combine them into a library (or a single object file), but otherwise, you're going to have to link to all such object file.