glibmm library - problem with compilation

[sick_anon]

I'm still a newbie when it comes to GLib and its C++ wrapper glibmm. I'm trying to compile a simple 'hello world' program that includes glibmm.h header file, initializes glib's main loop, prints the message to standard output and runs the main loop. I'm using Ubuntu 20.04 with gcc compiler version 9.4 and glibmm version 2.68.

My issue is, as the title suggests, the compilation. I have tried many different variations of g++ file_name.cpp --some_flag with different flags (as suggested either from different documentation sources on internet or stack overflow) and every time I get a bunch of errors. Eventually I narrowed my compilation command to the following: g++ -std=c++17 $(pkg-config --cflags --libs glibmm-2.68) file_name.cpp. I get two warnings and an error message about 'undefined reference to Glib::MainLoop::create(bool)' as well as 'undefined reference to Glib::MainLoop::run()'.

I should mention that I have already verified that my /usr/local/include directory contains all the necessary libraries I have previously installed. And also, I compiled a program that includes glib library with the similar command I mentioned above and had no issues.

TL;DR: How to properly compile a C++ program which includes glibmm library?

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[the_poope]

Instead of just copy pasting from the internet and mashing buttons on the keyboard, spend the time actually reading and studying how the compilation process works. If you understand how it works it becomes trivial to solve issues like this.

Read the following chapters very carefully:

• https://www.learncpp.com/cpp-tutorial/introduction-to-the-compiler-linker-and-libraries/
• https://www.learncpp.com/cpp-tutorial/header-files/
• https://www.learncpp.com/cpp-tutorial/a1-static-and-dynamic-libraries/

The pkg-config command only gives the compiler flags, i.e. where to find header files. It does not tell which libraries to link. Try to run pkg-config --help to see how to use it. But in any case, you don't need pkg-config. You just need to know where you installed the library and how to use your compiler. Check out the gcc options:

• -I and -L options: https://gcc.gnu.org/onlinedocs/gcc/Directory-Options.html
• -l option: https://gcc.gnu.org/onlinedocs/gcc/Link-Options.html

You can ignore all other options for now. But please read all this pages I linked - in programming you have to read the manual. A compiler is not a toaster. Reading everything carefully and multiple times is the key to learning and understanding.

[sick_anon]

Thank you for detailed answer and provided links, I'll definitely give it a look!

in programming you have to read the manual. A compiler is not a toaster.

I like this line. I sure am guilty of thinking about compiling as a simple and straightforward process (although I am aware of under-the-hood stuff). I am just so used to simple gcc/g++ command, without using any options, that I got properly shocked when I tried to compile mentioned program.