_Generic.3: Remove example code

Casting sockaddr structures is just a symptom that these APIs were
seriously misdesigned.  In GNU C, there's already a better way to handle
this (see [[gnu::transparent_union]]).  ISO C should be fixed.  Let's
not promote this kind of code.

Signed-off-by: Alejandro Colomar <alx@kernel.org>

diff --git a/man3/_Generic.3 b/man3/_Generic.3
index 6ff5e24ea76a871fb3fb1c9f510ead406bdb58a6..db1620f5f47582883ff1b0023668d0d5173d8633 100644 (file)
--- a/man3/_Generic.3
+++ b/man3/_Generic.3
@@ -27,95 +27,6 @@ that will behave differently depending on the type of the argument.
 .SH STANDARDS
 C11 and later.
 .SH EXAMPLES
-The following code demonstrates how to write
-a macro similar to C++'s
-.BR \%static_cast (),
-which will allow casting safely between a limited set of types.
-It is useful for example when calling
-system calls or library functions that use compatible structures,
-like for example
-.BR bind (2)
-with
-.BR \%sockaddr (3type).
-.IP
-.EX
-/* This code is in the public domain. */
-
-#include <netinet/in.h>
-#include <sys/socket.h>
-#include <sys/un.h>
-
-#define sockaddr_cast(t, p)                            \e
-    _Generic(&*(p),                                    \e
-    struct sockaddr *:                                 \e
-        _Generic((typeof_unqual(t)) NULL,              \e
-        struct sockaddr_in *:             (t) (p),     \e
-        struct sockaddr_in6 *:            (t) (p),     \e
-        struct sockaddr_un *:             (t) (p),     \e
-        default:                              (p)),    \e
-    struct sockaddr **:                                \e
-        _Generic((typeof_unqual(t)) NULL,              \e
-        struct sockaddr_in **:            (t) (p),     \e
-        struct sockaddr_in6 **:           (t) (p),     \e
-        struct sockaddr_un **:            (t) (p),     \e
-        default:                              (p)),    \e
-    const struct sockaddr *:                           \e
-        _Generic((t) NULL,                             \e
-        const struct sockaddr_in *:       (t) (p),     \e
-        const struct sockaddr_in6 *:      (t) (p),     \e
-        const struct sockaddr_un *:       (t) (p),     \e
-        default:                              (p)),    \e
-                                                       \e
-    struct sockaddr_in *:                              \e
-        _Generic((typeof_unqual(t)) NULL,              \e
-        struct sockaddr *:                (t) (p),     \e
-        default:                              (p)),    \e
-    struct sockaddr_in **:                             \e
-        _Generic((typeof_unqual(t)) NULL,              \e
-        struct sockaddr **:               (t) (p),     \e
-        default:                              (p)),    \e
-    const struct sockaddr_in *:                        \e
-        _Generic((t) NULL,                             \e
-        const struct sockaddr *:          (t) (p),     \e
-        default:                              (p)),    \e
-                                                       \e
-    struct sockaddr_in6 *:                             \e
-        _Generic((typeof_unqual(t)) NULL,              \e
-        struct sockaddr *:                (t) (p),     \e
-        default:                              (p)),    \e
-    struct sockaddr_in6 **:                            \e
-        _Generic((typeof_unqual(t)) NULL,              \e
-        struct sockaddr **:               (t) (p),     \e
-        default:                              (p)),    \e
-    const struct sockaddr_in6 *:                       \e
-        _Generic((t) NULL,                             \e
-        const struct sockaddr *:          (t) (p),     \e
-        default:                              (p)),    \e
-                                                       \e
-    struct sockaddr_un *:                              \e
-        _Generic((typeof_unqual(t)) NULL,              \e
-        struct sockaddr *:                (t) (p),     \e
-        default:                              (p)),    \e
-    struct sockaddr_un **:                             \e
-        _Generic((typeof_unqual(t)) NULL,              \e
-        struct sockaddr **:               (t) (p),     \e
-        default:                              (p)),    \e
-    const struct sockaddr_un *:                        \e
-        _Generic((t) NULL,                             \e
-        const struct sockaddr *:          (t) (p),     \e
-        default:                              (p)),    \e
-                                                       \e
-    default:                                           \e
-        (p)                                            \e
-    )
-
-socklen_t           slen;
-struct sockaddr_un  sun;
-
-slen = sizeof(ss);
-getsockname(sfd, sockaddr_cast(struct sockaddr *, &sun), &slen);
-.EE
-.PP
 The following program demonstrates how to write
 a replacement for the standard
 .BR imaxabs (3)