Bruno Haible wrote:
>Derek Price wrote:
>
>
>>This is what I installed.
>>
>>
>
>Note that lib/ and m4/ have ChangeLogs of their own. Only the top-level
>and modules/* modifications go into the top-level ChangeLog. Including
>the update of MODULES.html.sh (adding one line for each new module).
>
>
Thank you. I will use these ChangeLogs in the future.
>Three further remarks:
>
>- In the include file, you use size_t without including <stddef.h>. Won't
> work on platforms where unistd.h doesn't exist.
>
>
Looks like Paul got ahead of me and installed this first.
>- The documentation: When a programmer wants to know what the function does,
> he doesn't need/want to know how the function is implemented. Patch
> appended.
>
>
Installed.
>- The code in getlogin_r.c: Why do you save and restore errno? It's useless,
> since 1. POSIX doesn't say that errno is preserved (generally it's the
> caller's duty to save errno if he wants to),
>
Section 7.1.4 of the C89 spec states, "The value of errno ... is never
set to zero by any library function." I am assuming that getlogin_r and
probably most other GNULIB functions should act like library functions
when possible?
>2. you don't restore it
> before "return errno;".
>
>
I restore errno only when it was not set. Otherwise, I am intentionally
allowing errno to be set. This isn't POSIX compliant to the point of
not having side-effects not specified explicitly by POSIX, but this is
what the glibc getlogin_r function is doing and what it is documented to
do and I chose to emulate that behavior.
I was about to install the attached patch, which is more careful about
always restoring errno when it would have been set to zero, when Paul
beat me to the punch. I am not adverse to always restoring errno and
will leave things as Paul set them if you wish, but I still object to
never restoring it. (I would rather have no side-effects involving
errno rather than always setting it, sometimes to zero.) Is there some
reason we shouldn't comply with the C89 errno specification for library
functions?
I've also added getlogin_r to the POSIX.2001 support section of
MODULES.html.sh.
2005-05-25 Derek Price <[EMAIL PROTECTED]>
* MODULES.html.sh: Add getlogin_r to POSIX.2001 support section.
2005-05-25 Bruno Haible <[EMAIL PROTECTED]>
Derek Price <[EMAIL PROTECTED]>
* lib/getlogin_r.h: Simplify API documentation.
* lib/getlogin_r.c: Be more careful about restoring errno when
reset.
Regards,
Derek
Index: lib/getlogin_r.c
===================================================================
RCS file: /cvsroot/gnulib/gnulib/lib/getlogin_r.c,v
retrieving revision 1.1
diff -u -p -r1.1 getlogin_r.c
--- lib/getlogin_r.c 25 May 2005 14:21:20 -0000 1.1
+++ lib/getlogin_r.c 25 May 2005 18:43:32 -0000
@@ -39,6 +39,7 @@ getlogin_r (char *name, size_t size)
{
char *n;
int save_errno = errno;
+ int retval = -1;
errno = 0;
n = getlogin ();
@@ -48,12 +49,14 @@ getlogin_r (char *name, size_t size)
if (nlen < size)
{
memcpy (name, n, nlen + 1);
- return 0;
+ retval = 0;
}
- errno = ERANGE;
+ else
+ retval = ERANGE;
}
- if (errno) return errno;
- errno = save_errno;
- return -1;
+ if (errno) retval = errno;
+ else errno = save_errno;
+
+ return retval;
}
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