On Wed, Apr 27, 2011 at 07:19:42AM -0400, Wietse Venema wrote:
> Just because a system has getpwnam_r(), that does not mean it works
> like your API; and on some systems, getpwnam() does report errors
> via errno (e.g. FreeBSD8), whereas the original UNIX getpwnam()
> never returned for transient errors, because all reads were from
> local files.
Indeed the history of getpwnam_r() is not necessarily conformant with
the POSIX spec:
http://pubs.opengroup.org/onlinepubs/9699919799/functions/getpwnam.html
which specifies authoritative "not found" as a non-error, and other not-found
conditions as errors. For example, SunOS 5.8:
SYNOPSIS
#include <pwd.h>
struct passwd *getpwnam(const char *name);
struct passwd *getpwnam_r(const char *name, struct passwd
*pwd, char *buffer, int buflen);
[...]
POSIX
cc [ flag...] file... -D_POSIX_PTHREAD_SEMANTICS [ library... ]
int getpwnam_r(const char *name, struct passwd *pwd, char
*buffer, size_t bufsize, struct passwd **result);
[...]
Solaris 2.4 and earlier releases provided definitions of the
getpwnam_r() and getpwuid_r() functions as specified in
POSIX.1c Draft 6. The final POSIX.1c standard changed the
interface for these functions. Support for the Draft 6
interface is provided for compatibility only and might not
be supported in future releases. New applications and
libraries should use the standard-conforming interface.
For POSIX.1c-conforming applications, the
_POSIX_PTHREAD_SEMANTICS and _REENTRANT flags are automati-
cally turned on by defining the _POSIX_C_SOURCE flag with a
value >= 199506L.
Naturally, SunOS maintains backwards compatibility, so the same applies
to SunOS 5.10. The POSIX interface requires the _POSIX_PTHREAD_SEMANTICS
flag.
--
Viktor.
