1 files changed, 72 insertions, 0 deletions

diff --git a/gl/m4/inet_pton.m4 b/gl/m4/inet_pton.m4
new file mode 100644
index 00000000..b6e59a25
--- /dev/null
+++ b/gl/m4/inet_pton.m4
@@ -0,0 +1,72 @@
+# inet_pton.m4
+# serial 20
+dnl Copyright (C) 2006, 2008-2025 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+dnl This file is offered as-is, without any warranty.
+
+AC_DEFUN([gl_FUNC_INET_PTON],
+[
+  AC_REQUIRE([gl_ARPA_INET_H_DEFAULTS])
+
+  dnl Persuade Solaris <arpa/inet.h> to declare inet_pton.
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+  AC_REQUIRE([AC_C_RESTRICT])
+
+  dnl Most platforms that provide inet_pton define it in libc.
+  dnl Solaris 8..10 provide inet_pton in libnsl instead.
+  dnl Solaris 2.6..7 provide inet_pton in libresolv instead.
+  dnl Haiku provides it in -lnetwork.
+  dnl Native Windows provides it in -lws2_32 instead, with a declaration in
+  dnl <ws2tcpip.h>, and it uses stdcall calling convention, not cdecl
+  dnl (hence we cannot use AC_CHECK_FUNCS, AC_SEARCH_LIBS to find it).
+  HAVE_INET_PTON=1
+  INET_PTON_LIB=
+  gl_PREREQ_SYS_H_WINSOCK2
+  if test $HAVE_WINSOCK2_H = 1; then
+    dnl It needs to be overridden, because the stdcall calling convention
+    dnl is not compliant with POSIX.  Set REPLACE_INET_PTON in order to avoid
+    dnl a name conflict at the linker level, even though the header file
+    dnl <ws2tcpip.h> declares inet_pton only if _WIN32_WINNT >= 0x0600.
+    REPLACE_INET_PTON=1
+    AC_CHECK_DECLS([inet_pton],,, [[#include <ws2tcpip.h>]])
+    if test $ac_cv_have_decl_inet_pton = yes; then
+      INET_PTON_LIB="-lws2_32"
+    else
+      HAVE_DECL_INET_PTON=0
+    fi
+  else
+    gl_saved_LIBS=$LIBS
+    AC_SEARCH_LIBS([inet_pton], [nsl resolv network], [],
+      [AC_CHECK_FUNCS([inet_pton])
+       if test $ac_cv_func_inet_pton = no; then
+         HAVE_INET_PTON=0
+       fi
+      ])
+    LIBS=$gl_saved_LIBS
+
+    if test "$ac_cv_search_inet_pton" != "no" \
+       && test "$ac_cv_search_inet_pton" != "none required"; then
+      INET_PTON_LIB="$ac_cv_search_inet_pton"
+    fi
+
+    AC_CHECK_HEADERS_ONCE([netdb.h])
+    AC_CHECK_DECLS([inet_pton],,,
+      [[#include <arpa/inet.h>
+        #if HAVE_NETDB_H
+        # include <netdb.h>
+        #endif
+      ]])
+    if test $ac_cv_have_decl_inet_pton = no; then
+      HAVE_DECL_INET_PTON=0
+    fi
+  fi
+  AC_SUBST([INET_PTON_LIB])
+])
+
+# Prerequisites of lib/inet_pton.c.
+AC_DEFUN([gl_PREREQ_INET_PTON], [
+  AC_REQUIRE([gl_SOCKET_FAMILIES])
+])