C/C++ full file path in assert macro

Question

hello,

I am wondering if it's possible to display full file path using the assert macro? I cannot specify full file path in compilation command, is there still a way to do it?

My debug environment is linux/g++

Answer 1

assert uses the __FILE__ macro to get the filename. It will expand to the path used during compilation. For example, using this program:

#include <stdio.h>
int main(void)
{
    printf("%s\n", __FILE__);
    return 0;
}

If I compile with 'gcc -o foo foo.c' and run, I'll get this output:

foo.c

But if I compile with 'gcc -o foo /tmp/foo.c' and run, I'll get this output instead:

/tmp/foo.c

Answer 2

You can add the following macro option into your compilation line (Can be easily modify for your environment)

%.o: %.cpp
    $(CC) $(CFLAGS) -D__ABSFILE__='"$(realpath $<)"' -c $< -o $@

then you just have to this to have your full path:

#include <stdio.h>
int main()
{
  printf(__ABSFILE__);
  // will be expanded as: printf("/tmp/foo.c")
}

EDIT

Even better than this: The following rules is enough !!!

%.o: %.cpp
    $(CC) $(CFLAGS) -c $(realpath $<) -o $@

And you can now use __FILE__ macro:

#include <stdio.h>
int main()
{
  printf(__FILE__);
  // will be expanded as: printf("/tmp/foo.c")
}