/*
- * (c) The GRASP/AQUA Project, Glasgow University, 1994-1998
+ * (c) The GRASP/AQUA Project, Glasgow University, 1994-2002
*
- * $Id: inputReady.c,v 1.4 2001/12/21 15:07:26 simonmar Exp $
- *
- * hReady Runtime Support
+ * hWaitForInput Runtime Support
*/
/* select and supporting types is not Posix */
/* #include "PosixSource.h" */
-#include "HsCore.h"
+#include "HsBase.h"
/*
* inputReady(fd) checks to see whether input is available on the file
int
inputReady(int fd, int msecs, int isSock)
{
- if
-#ifndef mingw32_TARGET_OS
+ if
+#ifndef mingw32_HOST_OS
( 1 ) {
#else
( isSock ) {
#endif
- int maxfd, ready;
- fd_set rfd;
- struct timeval tv;
-
- FD_ZERO(&rfd);
- FD_SET(fd, &rfd);
-
- /* select() will consider the descriptor set in the range of 0 to
- * (maxfd-1)
- */
- maxfd = fd + 1;
- tv.tv_sec = msecs / 1000;
- tv.tv_usec = msecs % 1000;
+ int maxfd, ready;
+ fd_set rfd;
+ struct timeval tv;
+
+ FD_ZERO(&rfd);
+ FD_SET(fd, &rfd);
+
+ /* select() will consider the descriptor set in the range of 0 to
+ * (maxfd-1)
+ */
+ maxfd = fd + 1;
+ tv.tv_sec = msecs / 1000;
+ tv.tv_usec = (msecs % 1000) * 1000;
+
+ while ((ready = select(maxfd, &rfd, NULL, NULL, &tv)) < 0 ) {
+ if (errno != EINTR ) {
+ return -1;
+ }
+ }
+
+ /* 1 => Input ready, 0 => not ready, -1 => error */
+ return (ready);
+ }
+#ifdef mingw32_HOST_OS
+ else {
+ DWORD rc;
+ HANDLE hFile = (HANDLE)_get_osfhandle(fd);
+ DWORD avail;
- while ((ready = select(maxfd, &rfd, NULL, NULL, &tv)) < 0 ) {
- if (errno != EINTR ) {
- return -1;
- }
- }
+ // 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;
+ }
+ }
- /* 1 => Input ready, 0 => not ready, -1 => error */
- return (ready);
-#ifdef mingw32_TARGET_OS
- } else {
- DWORD rc;
- HANDLE hFile = (HANDLE)_get_osfhandle(fd);
-
- rc = MsgWaitForMultipleObjects( 1,
- &hFile,
- FALSE, /* wait all */
- msecs, /*millisecs*/
- QS_ALLEVENTS);
-
- /* 1 => Input ready, 0 => not ready, -1 => error */
- switch (rc) {
- case WAIT_TIMEOUT: return 0;
- case WAIT_OBJECT_0: return 1;
- default: return -1;
- }
+ rc = WaitForMultipleObjects( 1,
+ &hFile,
+ TRUE, /* wait all */
+ msecs); /*millisecs*/
+
+ /* 1 => Input ready, 0 => not ready, -1 => error */
+ switch (rc) {
+ case WAIT_TIMEOUT: return 0;
+ case WAIT_OBJECT_0: return 1;
+ default: return -1;
+ }
}
#endif
- }}
+}