From: Hans-Bernhard Broeker Newsgroups: comp.os.msdos.djgpp Subject: Re: C Library: mmap() function Date: 26 Sep 2000 15:36:16 GMT Organization: Aachen University of Technology (RWTH) Lines: 25 Message-ID: <8qqfpg$f04$1@nets3.rz.RWTH-Aachen.DE> References: <969980620 DOT 314295 AT shelley DOT paradise DOT net DOT nz> NNTP-Posting-Host: acp3bf.physik.rwth-aachen.de X-Trace: nets3.rz.RWTH-Aachen.DE 969982576 15364 137.226.32.75 (26 Sep 2000 15:36:16 GMT) X-Complaints-To: abuse AT rwth-aachen DOT de NNTP-Posting-Date: 26 Sep 2000 15:36:16 GMT Originator: broeker@ To: djgpp AT delorie DOT com DJ-Gateway: from newsgroup comp.os.msdos.djgpp Reply-To: djgpp AT delorie DOT com Edmund Horner wrote: > Can the mmap() function be implemented in the DJGPP libc? mmap(), originally, is not a libc feature, but provided by the system. DPMI doesn't provide this feature, AFAIK, so we'ld have to simulate it. The problem with such a simulation is that it would lose all the positive effects of mmap(), compared to straight-forward file I/O, which originally made it a good idea on Unix. We have no alternative to just doing the file I/O, in order to emulate mmap(), killing any advantage it may have. I.e., even if it is possible to simulate mmap(), DJGPP might very well be better off without it, forcing applications to use their own alternatives meant for mmap()-less systems. > If so, would it be a simple port from, say, the Linux glibc source, or would > it (as I suspect) involve a lot of fiddling with DPMI? Linux glibc wouldn't help a bit. mmap() is a system call, by nature, i.e. the source to copy from would be the kernel, not the libc. -- Hans-Bernhard Broeker (broeker AT physik DOT rwth-aachen DOT de) Even if all the snow were burnt, ashes would remain.