[lwip-users] errno is not set in sockets.c

[Mason]

Hello,

I am porting libcurl on top of lwip on a POSIX platform.
(libcurl uses the BSD sockets API, and non-blocking sockets.)

Calling connect on a non-blocking socket is supposed to
return EINPROGRESS in errno, but in my port, errno is
not set.

Looking at sockets.c, the relevant code is:

#ifdef ERRNO
#ifndef set_errno
#define set_errno(err) errno = (err)
#endif
#else /* ERRNO */
#define set_errno(err)
#endif /* ERRNO */

#define sock_set_errno(sk, e) do { \
  sk->err = (e); \
  set_errno(sk->err); \
} while (0)

If ERRNO is undefined, set_errno is a NOP, thus errno is never set.

What is the semantics / meaning of the ERRNO macro?

It is only checked in sockets.c
(and it is not set in my platform's system headers)
$ grep -rn "[^_]ERRNO" src
src/api/sockets.c:161:#ifdef ERRNO
src/api/sockets.c:165:#else /* ERRNO */
src/api/sockets.c:167:#endif /* ERRNO */

The unix port leaves ERRNO undefined, which means errno is never
set in the unix port (?!)

I'm familiar with the LWIP_PROVIDE_ERRNO macro, which I did NOT
define because I've included my platform's errno.h in cc.h

I propose deleting this ERRNO stuff:

--- sockets.c.orig      2012-02-23 10:57:12.796875000 +0100
+++ sockets.c   2012-03-20 10:50:40.375000000 +0100
@@ -158,13 +158,9 @@
   ((unsigned)(-(err)) < ERR_TO_ERRNO_TABLE_SIZE ? \
     err_to_errno_table[-(err)] : EIO)

-#ifdef ERRNO
 #ifndef set_errno
 #define set_errno(err) errno = (err)
 #endif
-#else /* ERRNO */
-#define set_errno(err)
-#endif /* ERRNO */

 #define sock_set_errno(sk, e) do { \
   sk->err = (e); \

(If someone wants his port to leave errno intact, they should
define set_errno to a NOP in his port's cc.h)

Did I miss something obvious, or something not so obvious?

-- 
Regards.