[project @ 2001-06-06 11:03:48 by simonmar]

[ghc-hetmet.git] / ghc / lib / std / cbits / inputReady.c

diff --git a/ghc/lib/std/cbits/inputReady.c b/ghc/lib/std/cbits/inputReady.c
index 2e07fcf..00b2d92 100644 (file)
--- a/ghc/lib/std/cbits/inputReady.c
+++ b/ghc/lib/std/cbits/inputReady.c
@@ -1,7 +1,7 @@
 /* 
  * (c) The GRASP/AQUA Project, Glasgow University, 1994-1998
  *
- * $Id: inputReady.c,v 1.4 1999/03/01 09:23:58 sof Exp $
+ * $Id: inputReady.c,v 1.7 2001/05/18 16:54:06 simonmar Exp $
  *
  * hReady Runtime Support
  */
@@ -11,87 +11,43 @@
 #define NON_POSIX_SOURCE  
 #endif
 
-#include "Rts.h"
-#include "stgio.h"
-
-#ifdef HAVE_SYS_TYPES_H
-#include <sys/types.h>
-#endif
-
-#ifdef _AIX 
-/* this is included from sys/types.h only if _BSD is defined. */
-/* Since it is not, I include it here. - andre */
-#include <sys/select.h>
-#endif
-
-#ifdef HAVE_UNISTD_H
-#include <unistd.h>
-#endif
-
-#ifdef HAVE_FCNTL_H
-#include <fcntl.h>
-#endif
-
-#ifdef HAVE_SYS_TIME_H
-#include <sys/time.h>
-#endif
+#include "HsStd.h"
 
 /*
- * inputReady(ptr, msecs) checks to see whether input is available
- * on the file object 'ptr', timing out after (approx.) 'msec' milliseconds.
- * Input meaning 'can I safely read at least a *character* from this file
- * object without blocking?'
- * 
- * If the file object has a non-empty buffer, the test is trivial. If not,
- * we select() on the (readable) file descriptor.
- *
- * Notice that for file descriptors connected to ttys in non-canonical mode
- * (i.e., it's buffered), inputReady will not return true until a *complete
- * line* can be read.
+ * inputReady(fd) checks to see whether input is available on the file
+ * descriptor 'fd'.  Input meaning 'can I safely read at least a
+ * *character* from this file object without blocking?'
  */
-
-StgInt
-inputReady(ptr, msecs)
-StgForeignPtr ptr;
-StgInt msecs;
+int
+inputReady(int fd, int msecs)
 {
-    IOFileObject* fo = (IOFileObject*)ptr;
-    int c, fd, maxfd, ready;
+    int maxfd, ready;
 #ifndef mingw32_TARGET_OS
     fd_set rfd;
     struct timeval tv;
 #endif
 
-    if ( FILEOBJ_IS_EOF(fo) )
-       return 0;
-
-    if ( !FILEOBJ_BUFFER_EMPTY(fo) ) {
-          /* Don't look any further, there's stuff in the buffer */
-          return 1;
-    }
-
 #ifdef mingw32_TARGET_OS
-    return 0;
+    return 1;
 #else
-    fd = fo->fd;
-
-    /* Now try to get a character */
     FD_ZERO(&rfd);
     FD_SET(fd, &rfd);
-    /* select() will consider the descriptor set in the range of 0 to (maxfd-1) */
+
+    /* 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;
+
     while ((ready = select(maxfd, &rfd, NULL, NULL, &tv)) < 0 ) {
       if (errno != EINTR ) {
-               cvtErrno();
-               stdErrno();
-                ready = -1;
-               break;
+          return -1;
       }
    }
 
-    /* 1 => Input ready, 0 => time expired  (-1 error) */
+    /* 1 => Input ready, 0 => not ready, -1 => error */
     return (ready);
+
 #endif
 }