Question

I have a file module.hpp

struct ModuleBase {
    virtual void run() = 0;
};

and a main.cpp program

int main() {
    cout << ...?...; // here should go the contents of module.hpp
}

What can I put at ...?... to let the contents of the header file printed here?

A basic idea would be

int main() {
    static const string content = R"(
#include <module.hpp>
)";
    cout << content;
}

but multi-line-strings are only available in C++11, and #include does not work inside multi-line strings (which is good)?

If there is a non-portable way for the gcc… that would be a start.

Clarification (update): The substitution should be done at compile time.

Answer 1

The only real solution I know is to write a small program which
converts a file into a C++ definition of a string variable
containing it. This is fairly simple to write: output a simple
header along the lines of:

char const variableName[] =

Then copy each line of the file, wrapping it in "...\n", and
escaping any characters necessary. (If you can be sure of
C++11, then you might be able to do something with R"...", but
I’ve no experience with this.)

[update: refering to the original question with a typo in it]:
Your solution should not work; if it does, it is an error in
the compiler. According to §2.2, tokenization occurs before
the execution of preprocessing directives. So when the
execution of preprocessing directives occurs, you have a string
literal, and not a # preprocessing token. (Compiler errors
are to be expected when using C++11 features. There’s not been
enough time yet for the implementers to get all of the bugs
out.)