Bruno Haible wrote:
>Would you mind adding a bit of documentation? Something like
>
I've added the following to getlogin_r.h:
/* Copies the user's login name to NAME.
The array pointed to by NAME has room for SIZE bytes.
Returns 0 if successful. Upon error, an error number is returned, or
-1 in
the case that the login name cannot be found but no specific error is
provided by getlogin (getlogin returned NULL and did not set errno - this
case is hopefully rare but is left open by the POSIX spec).
See
<http://www.opengroup.org/onlinepubs/009695399/functions/getlogin.html>.
*/
>The return value is incorrect, and the getlogin () return conventions are
>ignored.
>
>http://www.opengroup.org/onlinepubs/009695399/functions/getlogin.html
>says:
>
> "Upon successful completion, getlogin() shall return a pointer to the login
> name or a null pointer if the user's login name cannot be found.
> Otherwise, it shall return a null pointer and set errno to indicate the
> error."
>
>Which means, you need to set errno = 0 before calling getlogin(), to
>distinguish two of the three cases.
>
>And
>
> "If successful, the getlogin_r() function shall return zero; otherwise,
> an error number shall be returned to indicate the error."
>
>So, instead of "errno = ERANGE; return -1; " you need to do "return ERANGE;".
>
>
This is what I installed. It sets *and* returns errno since my local
man pages make it sound like errno will be set by getlogin_r and others
may already have code which checks errno and not getlogin_r's return
value. I would note that the opengroup POSIX spec you reference does
not define an error return code for getlogin_r for the case where "the
user's login name cannot be found". I chose -1 arbitrarily. Glancing
at the code in glibc-2.3.5, it looks like it also sets and returns
errno, though they return ENOENT as an extension to the POSIX spec when
the login name cannot be found.
/* See getlogin_r.h for documentation. */
int
getlogin_r (char *name, size_t size)
{
char *n;
int save_errno = errno;
errno = 0;
n = getlogin ();
if (n)
{
size_t nlen = strlen (n);
if (nlen < size)
{
memcpy (name, n, nlen + 1);
return 0;
}
errno = ERANGE;
}
if (errno) return errno;
errno = save_errno;
return -1;
}
2005-05-25 Derek Price <[EMAIL PROTECTED]>
Paul Eggert <[EMAIL PROTECTED]>
* lib/getlogin_r.c, lib/getlogin_r.h, m4/getlogin_r.m4,
modules/getlogin_r: New files.
Regards,
Derek
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