From: mason@primenet.com.au (Geoff Wing)
To: zsh-workers@sunsite.auc.dk
Subject: Re: Bad configure test for getpwent() ?
Date: 3 Nov 1999 19:58:35 GMT [thread overview]
Message-ID: <slrn8214vb.pbp.mason@coral.primenet.com.au> (raw)
In-Reply-To: <19991103133904.A6549@dman.com>
Clint Adams <schizo@debian.org> typed:
:> pw1=getpwnam(buf);
:> sprintf(buf, "%d:%d", rand(), getpid());
:> pw2=getpwnam(buf);
:> exit(pw1!=0 && pw2!=0 && !strcmp(pw1->pw_name, pw2->pw_name));
:
:It's not comparing the pointers; it's comparing the names.
:
:> I don't think getpwent() is required to return a unique pointer each time;
:> that is, I think it's allowed to re-use an internal static buffer for each
:> entry that it returns. That would mean that this test always succeeds ...
My man page says:
BUGS
The functions getpwent(), getpwnam(), and getpwuid(), leave their results
in an internal static object and return a pointer to that object. Subse-
quent calls to any of these functions will modify the same object.
On my system then, pw2 will be the same as pw1.
Bart typed:
:I think the only right way is to test the first pointer for nonzero, copy
:the entry into a local struct passwd, then call getpwent() again and do
:the comparison.
I'd say this is correct.
Regards,
--
Geoff Wing : <gcw@pobox.com> Work URL: http://www.primenet.com.au/
Rxvt Stuff : <gcw@rxvt.org> Ego URL : http://pobox.com/~gcw/
Zsh Stuff : <gcw@zsh.org> Phone : (Australia) 0413 431 874
next prev parent reply other threads:[~1999-11-03 19:58 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-11-03 10:34 Bart Schaefer
1999-11-03 18:39 ` Clint Adams
1999-11-03 19:58 ` Geoff Wing [this message]
1999-11-03 20:04 ` Clint Adams
1999-11-03 20:14 ` Bart Schaefer
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