X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fisatty.c;fp=lib%2Fisatty.c;h=2ecdd5494a4c1ad082ec6d3e1af9afedec01e807;hb=5eb934dfd78a8ff086ffef87f5d4ec18e2d45cf7;hp=42424535831794dcdc3c7fd29a97e79a89dfadd9;hpb=4e9e5f62f6a6d5488f0697cb38c8c7847a25ebf8;p=gnulib.git

diff --git a/lib/isatty.c b/lib/isatty.c
index 424245358..2ecdd5494 100644
--- a/lib/isatty.c
+++ b/lib/isatty.c
@@ -48,8 +48,7 @@ _isatty_nothrow (int fd)
     }
   CATCH_MSVC_INVAL
     {
-      result = -1;
-      errno = EBADF;
+      result = 0;
     }
   DONE_MSVC_INVAL;
 
@@ -59,15 +58,24 @@ _isatty_nothrow (int fd)
 # define _isatty_nothrow _isatty
 #endif
 
+/* Determine whether FD refers to a console device.  Return 1 if yes.
+   Return 0 and set errno if no. (ptsname_r relies on the errno value.)  */
 int
 isatty (int fd)
 {
-  /* _isatty (fd) tests whether GetFileType of the handle is FILE_TYPE_CHAR.  */
+  HANDLE h = (HANDLE) _get_osfhandle (fd);
+  if (h == INVALID_HANDLE_VALUE)
+    {
+      errno = EBADF;
+      return 0;
+    }
+  /* _isatty (fd) tests whether GetFileType of the handle is FILE_TYPE_CHAR.
+     But it does not set errno when it returns 0.  */
   if (_isatty_nothrow (fd))
     {
-      HANDLE h = (HANDLE) _get_osfhandle (fd);
-      return IsConsoleHandle (h);
+      if (IsConsoleHandle (h))
+        return 1;
     }
-  else
-    return 0;
+  errno = ENOTTY;
+  return 0;
 }