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Re: [bug-gnulib] valloc()?
From: |
Bruno Haible |
Subject: |
Re: [bug-gnulib] valloc()? |
Date: |
Thu, 3 Mar 2005 21:47:51 +0100 |
User-agent: |
KMail/1.5 |
Derek Price wrote:
> I've attached a patch to fix a few more nits
Committed, with small wording tweaks in the comments.
> - I noticed that I assumed mmap() returns NULL on error when it
> actually returns MAP_FAILED according to POSIX.
Ouch, this was a major bug. Glad that you found it.
> - Note in the header that pagealign_alloc sets errno on failure.
But it doesn't do so if malloc() fails on non-POSIX systems (like mingw
or so). I think one should set errno = ENOMEM if malloc() fails.
> I had two further thoughts on the naming of mmap-anon.m4. First, in my
> original decision to name it mmap.m4, I did take into consideration that
> there might be other mmap.m4 implementations but, ideally, I would hope
> that their requirements could be merged into this mmap(-anon).m4, at the
> least for simplicity's sake.
I don't have this hope: The requirements of different programs regarding
mmap are so different that, if all tests were merged into a common mmap.m4
file, some people would say "this test is insane - it disables mmap on
SVR4 [or Linux 1.2 or HP-UX or ...] although it is perfectly sane".
SVR4 had problems with PRIVATE READ-WRITE mappings of files.
Linux 1.2 didn't support MAP_SHARED on files.
HP-UX doesn't support mapping files at fixed addresses in most cases.
> Second, technically what we are currently
> calling gl_FUNC_MMAP_ANON calls AC_FUNC_MMAP, so it also verifies that
> private, fixed maps to files work as well, not just anonymous maps.
Yes, this is one of the problems with AC_FUNC_MMAP. But fortunately we
can ignore it because nowadays most systems have a working mmap(), therefore
not many people will complain "it disables mmap() on my system".
Bruno
- Re: [bug-gnulib] valloc()?, (continued)
- Re: [bug-gnulib] valloc()?, Bruno Haible, 2005/03/03
- Re: [bug-gnulib] valloc()?, Derek Price, 2005/03/03
- Re: [bug-gnulib] valloc()?, Bruno Haible, 2005/03/03
- Re: [bug-gnulib] valloc()?, Derek Price, 2005/03/03
- Message not available
- Re: [bug-gnulib] valloc()?,
Bruno Haible <=
- Message not available
- Re: [bug-gnulib] valloc()?, Bruno Haible, 2005/03/04
- Re: [bug-gnulib] valloc()?, Derek Price, 2005/03/04
Re: [bug-gnulib] valloc()?, Larry Jones, 2005/03/03