Feature request: native Windows support

[aitap]

I have a Windows-only project that dmalloc could really help with. Currently, it seems that the only way to use dmalloc on Windows is to build it with Cygwin, since the only virtual memory APIs that dmalloc currently speaks are sbrk and mmap, and Windows has neither.

If you are interested in this, I could prepare a pull request modifying heap.c to use VirtualAlloc / VirtualFree in addition to mmap / munmap, bringing me closer to my goal of cross-compiling dmalloc for Windows using something like ./configure --build=i686-linux-gnu --host=i686-w64-mingw32. While lack of mmap could be worked around using INTERNAL_MEMORY_SPACE, it's not a good solution.

[aitap]

This is probably harder than it looks like:

• Functions in append.c pass va_lists to other functions, expecting state modifications done by va_arg() in the callee to persist in the caller. Apparently this is not the case for mingw (where va_list could be just a char *), so loc_snprintf(setup, sizeof(setup), "debug=%#x,start=%s:%d", 0x400, loc_file, loc_line); crashes while trying to dereference 0x400 instead of loc_file.
• For logging purposes, addresses are cast to long. Unfortunately, long is 32-bit in 64-bit Windows. Thankfully, there is only one long → DMALLOC_PNT cast, in env.c. Fixing this in a portable manner would be "fun".

[j256]

Thanks much @aitap . I don't quite understand your point. Am I doing something wrong with the va_list stuff or is there some incompatibility in it under windows?

[j256]

OH! I see it. I bet that's a bug. Let me see if I can reproduce it in testing.

[j256]

Fixed the va_args usage with #27

[j256]

I get the second bullet now. Hrm. So when we are printing the value as "%#lx" and I extract it as a long, that won't work. Maybe I should be more religious about %p and extract it as a char *?

[j256]

Is there a long long or some other 64 bit numerical type? I need something to be able to do arithmetic on the pointer to be able to display it.

[j256]

I just pushed up this pull request. Does it fix anything? #28

[aitap]

Thanks a lot for your help!

[j256]

Sure thing. Appreciate your feedback.