X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fptsname.m4;h=dd6f81dd14baade05be5fe0d4fb837ab39cc7da5;hb=72c63c089365640c7f1acd97fb72ee26932ac2b3;hp=4dba5f375ab411d1a7851c04f59499dea93ec626;hpb=30b81aa8c1b1d1beaa2057cfe9a6d589ccf334ad;p=gnulib.git

diff --git a/m4/ptsname.m4 b/m4/ptsname.m4
index 4dba5f375..dd6f81dd1 100644
--- a/m4/ptsname.m4
+++ b/m4/ptsname.m4
@@ -1,5 +1,5 @@
-# ptsname.m4 serial 2
-dnl Copyright (C) 2010-2011 Free Software Foundation, Inc.
+# ptsname.m4 serial 3
+dnl Copyright (C) 2010-2013 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.
@@ -14,6 +14,26 @@ AC_DEFUN([gl_FUNC_PTSNAME],
   AC_CHECK_FUNCS([ptsname])
   if test $ac_cv_func_ptsname = no; then
     HAVE_PTSNAME=0
+  else
+    AC_CACHE_CHECK([whether ptsname sets errno on failure],
+      [gl_cv_func_ptsname_sets_errno],
+      [AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM([[#include <errno.h>
+      ]], [[
+      return ptsname (-1) || !errno;
+           ]])],
+         [gl_cv_func_ptsname_sets_errno=yes],
+         [gl_cv_func_ptsname_sets_errno=no],
+         [case "$host_os" in
+                    # Guess yes on glibc systems.
+            *-gnu*) gl_cv_func_ptsname_sets_errno="guessing yes" ;;
+                    # If we don't know, assume the worst.
+            *)      gl_cv_func_ptsname_sets_errno="guessing no" ;;
+          esac
+         ])])
+    case $gl_cv_func_ptsname_sets_errno in
+      *no) REPLACE_PTSNAME=1 ;;
+    esac
   fi
 ])