I've been looking at the socklen_t mess - systems define it but do
not use it, use void*length instead of socklen_t*length, and so on.
Just how messy is this - is there even any point in trying to cover
enough possibilities that configure can fail if it doesn't find the
correct type? The following code comes from examining just 4 systems -
Linux, HP-UX, Solaris, OSF1. Googling around I found tests that
check for more intger types as well: unsigned, long, unsigned long
in addition to socklen_t, int and size_t. Which systems need these?
Also, do systems use the same type (or at least a type of the same size)
for getsockopt()'s and accept()'s last arg, or do I need a separate
getsockopt() test?
AC_CHECK_TYPE([socklen_t],,, [$ac_includes_default
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif])
dnl accept() sockaddr-length type. Notes:
dnl - The system might define socklen_t without actually using it.
dnl POSIX has moved from int to size_t to socklen_t, and at
dnl least HP-UX now has switches to select which version to use.
dnl - Look for the length type in the connect() prototype if we
dnl encounter accept(<...>, void *length). Happens on Solaris,
dnl even though their accept() manpage says socklen_t *length.
dnl - If we do not find the type, but socklen_t, int and size_t
dnl have the same size, we can likely use either if it compiles.
dnl With a chaos like this, such a fallback seems prudent.
dnl - Hopefully we do not need separate types for getsockopt().
AC_CACHE_CHECK([for accept() sockaddr-length type],ol_cv_type_lber_socklen_t,[
vtype=void
sltype=socklen_t ; test "$ac_cv_type_socklen_t" = yes || sltype=
step2=2 ; test "$ac_cv_sizeof_int" = "$ac_cv_sizeof_long" || step2=
for step in 0 1 $step2 ; do
test $step = 2 && vtype=
for lentype in $sltype int size_t ; do
for addrtype in "struct sockaddr" $vtype ; do
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([$ac_includes_default
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#if $step == 0
extern int accept(int s, $addrtype *ap, $lentype *lp);
#elif $step == 1 /* Solaris hack */
extern int accept(int s, $addrtype *ap, void *lp);
extern int connect(int s, const $addrtype *ap, $lentype l);
#else /* $step == 2: default if candidate types have the same size. */
enum { Check = sizeof($lentype)==sizeof(int) && sizeof(int)==sizeof(size_t) };
struct { int d: Check ? 1 : -1; } dummy[Check ? 1 : -1]; /* error if !Check */
#endif /* $step */
], [
static struct sockaddr *addrp;
static $lentype len;
accept(0, addrp, &len);
])], [ol_cv_type_lber_socklen_t=$lentype; break 3])
done
done
done])
if test -z "$ol_cv_type_lber_socklen_t" ; then
AC_MSG_FAILURE([accept() sockaddr-length type not found])
fi
AC_DEFINE_UNQUOTED(LBER_SOCKLEN_T, $ol_cv_type_lber_socklen_t,
[define to sockaddr-length type used by accept()])
--
Regards,
Hallvard
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