[project @ 2005-01-18 15:08:39 by simonmar]

Win32: attempt to make inputReady() work on pipes too.  Fixes bug
#995658.

diff --git a/cbits/inputReady.c b/cbits/inputReady.c
index 30e140b..a86f961 100644 (file)
--- a/cbits/inputReady.c
+++ b/cbits/inputReady.c
@@ -49,7 +49,32 @@ inputReady(int fd, int msecs, int isSock)
     else {
        DWORD rc;
        HANDLE hFile = (HANDLE)_get_osfhandle(fd);
-       
+       DWORD avail;
+
+       // WaitForMultipleObjects() works for Console input, but it
+       // doesn't work for pipes (it always returns WAIT_OBJECT_0
+       // even when no data is available).  There doesn't seem to be
+       // an easy way to distinguish the two kinds of HANDLE, so we
+       // try to detect pipe input first, and if that fails we try
+       // WaitForMultipleObjects().
+       //
+       rc = PeekNamedPipe( hFile, NULL, 0, NULL, &avail, NULL );
+       if (rc != 0) {
+           if (avail != 0) {
+               return 1;
+           } else {
+               return 0;
+           }
+       } else {
+           rc = GetLastError();
+           if (rc == ERROR_BROKEN_PIPE) {
+               return 1; // this is probably what we want
+           }
+           if (rc != ERROR_INVALID_HANDLE) {
+               return -1;
+           }
+       }
+
        rc = WaitForMultipleObjects( 1,
                                     &hFile,
                                     TRUE,   /* wait all */