Question

My project has a function that clears the terminal, which is implemented using the curses library. Compiling with the -lcurses flag works fine, but compiling without yeilds

/tmp/cc3T2MVI.o: In function `ClearScreen()':
clear_term.cpp:(.text+0xb): undefined reference to `cur_term'
clear_term.cpp:(.text+0x26): undefined reference to `setupterm'
clear_term.cpp:(.text+0x37): undefined reference to `tigetstr'
clear_term.cpp:(.text+0x3f): undefined reference to `putp'
collect2: ld returned 1 exit status

This is obviously expected because it cant find the library, but because this functionality is supplemental it would be preferable to define ClearScreen() as an empty function than to have compilation fail. I know that I put the function definition in a #ifdef block but I don’t know any flags defined by curses.

Is it possible to catch these errors and instead define ClearScreen() as an empty function?

Answer 1

You can define a macro in the Makefile:

use_curses=1
FLAGS+=-DUSING_MAKEFILE
ifeq ($(use_curses),0)
    FLAGS+=-DNO_NCURSES
else
    LIBS+=-lcurses
endif

And in the code:

#ifndef USING_MAKEFILE
#       error "Please use provided Makefile to compile!"
#endif

#ifdef NO_CURSES
        void ClearScreen() { }
#endif