conditional compilation based on existance of a symbol?

Hi,
I am writing a program that uses a function that doesn't currently exist in mingw (gettimeofday() in this case). I am doing my development on Linux/GCC, but I want to be able to compile my program everywhere.

I can define that function in terms of Win32 API.

What I have in mind is to conditionally define that function myself if it doesn't already exist.

I could do the condition based on __WIN32 or something of that sort, but I assume my code will break if/when mingw finally implements that function?

How can I do it?

Thank you

One way would be to write your own function and have separate implementations of it for Windows and *nix systems. For your windows implementation, you would have it call Windows API functions, possibly just as a 1:1 wrapper. Same concept for *nix.

hmm I see... why didn't i think of this =)

thank you for your help

how about using boost::date_time?

that would be a good idea, too, but since I am not using anything else from boost in this particular project, I am reluctant to add boost as a dependency just for this function.

Put you implementation of gettimeofday() in its own library, for instance libwindows_compat.a.

Then, EXPLICITLY list the C library on the link line, after everything else except the compat library, and place -lwindows_compat AFTER it:

Code:

---

$(LINK) -o myprogram $(MY_OBJS) $(MY_LIBS) -lc libwindows_compat.a

---

This causes the C library to be linked against BEFORE checking windows_compat. If some future version of the MinGW library includes a gettimeofday() function, it will be used, not the one in libwindows_compat.a

I see what you mean, but I have never written a library before =) looks quite complicated. I will google it up. Thank you for your help.