--On Tuesday, September 02, 2003 11:32:08 -0400 Bruce Momjian <[EMAIL PROTECTED]> wrote:
Larry Rosenman wrote:My take is unless otherwise stated, all libc functions are thread-safe on UnixWare.> Where does it say that you have to use getpwuid_r() to be thread safe? > I don't see any mention in the docs. It does say about getpwuid: > > For getpwent, getpwuid, getpwnam, setpwent, endpwent, and > fgetpwent, all information is contained in a static area, so it > must be copied if it is to be > > but that in itself doesn't mean it isn't thread safe. If you are not > sure, would you write a little thread program to test if it works if > two threads try it at the same time. I only have a UP box.
Since the _r version uses OUR OWN buffer, it is safer to use the _r version.
Since we do NOT have the _r alternative for strerror and gethostbyname, that's the best we can do.
Uh, that's not the logic I use. I have some *_r functions on BSD/OS, but the normal libc functions are thread-safe, so I just use those. I think I have the *_r functions because the standards require them to exist, not because they are required for thread-safety, and like Unixware, I have some of them, but not others (no strerror_r). Because Unixware is similar in that it has some *_r functions and not others, I want to know if getpwuid_r() is required.
gethostbyname() also returns data from a static area. Why is that thread-safe on Unixware and getpwuid() is not? My guess is that both are thread-safe but some software requires getpwuid_r() so they added it. Again, on those OS's, it is better to just use the libc versions.
"Safer" isn't an issue. Either it is safe or unsafe. I also don't care about locking overhead in the libc versions of these functions.
the *_r functions are better if available as they require the USER to allocate/pass
their OWN buffer. We should use those (that's the signature we use in src/port/thread.c),
but if they don't exist, we should just use the non-*_r version.
If the OS supports threads, this *should* work.
My $0.02.
LER
-- Larry Rosenman http://www.lerctr.org/~ler Phone: +1 972-414-9812 E-Mail: [EMAIL PROTECTED] US Mail: 1905 Steamboat Springs Drive, Garland, TX 75044-6749
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