fdl.texi from gnustandards

[gnulib.git] / m4 / ttyname_r.m4

diff --git a/m4/ttyname_r.m4 b/m4/ttyname_r.m4
index ce47374..c41d8ba 100644 (file)
--- a/m4/ttyname_r.m4
+++ b/m4/ttyname_r.m4
@@ -1,4 +1,4 @@
-# ttyname_r.m4 serial 2
+# ttyname_r.m4 serial 3
 dnl Copyright (C) 2010 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -8,11 +8,16 @@ AC_DEFUN([gl_FUNC_TTYNAME_R],
 [
   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
 
+  dnl Persuade Solaris <unistd.h> to provide the POSIX compliant declaration of
+  dnl ttyname_r().
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
   AC_CHECK_FUNCS([ttyname_r])
   if test $ac_cv_func_ttyname_r = no; then
     HAVE_TTYNAME_R=0
   else
-    dnl On MacOS X 10.4 and Solaris 10 the return type is 'char *', not 'int'.
+    dnl On MacOS X 10.4 (and Solaris 10 without gl_USE_SYSTEM_EXTENSIONS)
+    dnl the return type is 'char *', not 'int'.
     AC_CACHE_CHECK([whether ttyname_r is compatible with its POSIX signature],
       [gl_cv_func_ttyname_r_posix],
       [AC_COMPILE_IFELSE(
@@ -26,6 +31,47 @@ AC_DEFUN([gl_FUNC_TTYNAME_R],
       ])
     if test $gl_cv_func_ttyname_r_posix = no; then
       REPLACE_TTYNAME_R=1
+    else
+      AC_DEFINE([HAVE_POSIXDECL_TTYNAME_R], [1],
+        [Define if the ttyname_r function has a POSIX compliant declaration.])
+      dnl On Solaris 10, both ttyname_r functions (the one with the non-POSIX
+      dnl declaration and the one with the POSIX declaration) refuse to do
+      dnl anything when the output buffer is less than 128 bytes large.
+      AC_REQUIRE([AC_CANONICAL_HOST])
+      AC_CACHE_CHECK([whether ttyname_r works with small buffers],
+        [gl_cv_func_ttyname_r_works],
+        [
+          dnl Initial guess, used when cross-compiling or when /dev/tty cannot
+          dnl be opened.
+changequote(,)dnl
+          case "$host_os" in
+                      # Guess no on Solaris.
+            solaris*) gl_cv_func_ttyname_r_works="guessing no" ;;
+                      # Guess yes otherwise.
+            *)        gl_cv_func_ttyname_r_works="guessing yes" ;;
+          esac
+changequote([,])dnl
+          AC_TRY_RUN([
+#include <fcntl.h>
+#include <unistd.h>
+int
+main (void)
+{
+  int fd;
+  char buf[31]; /* use any size < 128 here */
+
+  fd = open ("/dev/tty", O_RDONLY);
+  if (fd < 0)
+    return 1;
+  if (ttyname_r (fd, buf, sizeof (buf)) != 0)
+    return 1;
+  return 0;
+}], [gl_cv_func_ttyname_r_works=yes], [:], [:])
+        ])
+      case "$gl_cv_func_ttyname_r_works" in
+        *yes) ;;
+        *) REPLACE_TTYNAME_R=1 ;;
+      esac
     fi
   fi
   if test $HAVE_TTYNAME_R = 0 || test $REPLACE_TTYNAME_R = 1; then