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DJGPP love Window$ ? (Developers)

posted by Rugxulo Homepage, Usono, 14.09.2013, 20:36

> did you enable long file name support on your DOS PC? DJGPP will not
> compile without that!
DJGPP intentionally can (and does) work with either LFNs (Win95) or no LFNs (MS-DOS 6.22). It totally depends on whether you unzipped (installed) DJGPP with an LFN-aware unzipper (and suitable TSR loaded, of course). If you want to use DJGPP with both SFN and LFN, you'll have to unzip twice. So some (but not all) files like "longfilename.txt" will exist twice as "longfile.txt" and "longfi~1.txt".

But most programs that people try to compile with DJGPP require LFNs and lots of POSIX tools (e.g. Bash for configure). So it may not "work" even if you do everything 100% correctly. Most modern programs just aren't designed to care about anything like DJGPP. But that is their problem (by design or ignorance), not ours.

> You can load doslfn and then it will compile, but MUCH, MUCH slower than in
> a Windows XP DOS box.
A while back, Juan recompiled DJGPP libc from CVS and timed it. It was actually 2x slower with LFNs than without.

> So I develop in a Windows XP DOS box or I would never
> get finished. I did not try it for a long time but I think it would take
> over an hour to compile Dillo in real mode DOS with doslfn loaded.
DJGPP is not fast. Or I should say GCC isn't very fast. You really need a cache loaded. And even then, a lot of it is still slower than ideal because it has to load lots of files to RAM from hard drive. Also, I'm not sure the linker is very optimal. It tries to do a billion optimizations, and it's not really geared towards compiling without it. In other words, you'd expect it to be 10x faster without optimizations, but it's not. If compile speed is important, DJGPP may not be for you. (Though careful use of makefiles can help prevent rebuilding unnecessary parts. You should really only recompile what's changed.) Oh yeah, lack of precompiled headers, blah blah blah. "Just use FPC!" ;-)

> I guess one could copy the required files to an XMSDISK and develop there
> but I did not try that yet.
Yes, a year ago I timed (re)compiling p7zip (G++) under bare FreeDOS with and without LFNs, both with compiler installed to RAM disk and traditional hard drive install. The fastest way was a). without LFNs (but needed lots of patching to the project, which always assumed certain names), and b). compiler itself installed to RAM (easily 2x or 3x faster than only cache + HD install).

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