g++: Compiling without -l flags

问题:

Simple question- are these any way to not have to call libraries during the compiling? I mean, I would like to simply call g++ main.cpp without calling g++ main.cpp -lGL -lGLU -lGLEW -lSTL -lMyMother and so on... I know, makefiles or simple shell scripting, but I would like to make it elegant way - call these libraries inside cpp code - something like 'using GL;'.

回答1:

Since you're using GCC, you could create/modify a specs file to add the flags you want.

If you don't like typing flags, you really should be using a makefile, though.

回答2:

Technically you can dynamically load libraries by dlopen() and call functions from it (I am assuming you are on *nix). Though that would be not the same thing and I doubt will make your life easier. Other than that there is no portable way of specifying which library to use in source file.

回答3:

On Linux you may use pkg-config and shell expansion. Use pkg-config --list-all to discover what packages are known to it (you might add a .pc file to add a new package). For instance, a GTK application mygtkapp.c could be compiled with

gcc -Wall -g $(pkg-config --cflags gtk+-x11-3.0) -c mygtkapp.c

then later linked with

gcc -g mygtkapp.o $(pkg-config --libs gtk+-x11-3.0) -o mygtkapp

Notice that order of arguments to gcc always matter. Of course use g++ to compile C++ applications with GCC.

Consider also using a Makefile like this one. Then just type make to build your software (and e.g. make clean to clean the build tree).

^{You might use weird tricks in your Makefile to e.g. parse with awk some comments in your C++ code to feed make but I think it is a bad idea.}

Technically, you still pass -I and -D flags (at compile time) and -L and -l flags (at link time) to gcc or g++ but the pkg-config utility (or make ....) is generating these flags.

If you edit your source code with emacs you could add a comment at end of your C file to set some compilation command for emacs, see this.

^{PS. I don't recommend configuring your GCC spec files for such purposes.}