1 files changed, 99 insertions, 0 deletions
diff --git a/ipl/cfuncs/fpoll.c b/ipl/cfuncs/fpoll.c
new file mode 100644
index 0000000..f209e0d
--- /dev/null
+++ b/ipl/cfuncs/fpoll.c
@@ -0,0 +1,99 @@
+/*
+############################################################################
+#
+#	File:     fpoll.c
+#
+#	Subject:  Function to poll file for input
+#
+#	Author:   Gregg M. Townsend
+#
+#	Date:     November 27, 2001
+#
+############################################################################
+#
+#   This file is in the public domain.
+#
+############################################################################
+#
+#  fpoll(f, msec) waits until data is available for input from file f,
+#  and then returns.  It also returns when end-of-file is reached.
+#  If msec is specified, and no data is available after waiting that
+#  many milliseconds, then fpoll fails.  If msec is omitted, fpoll
+#  waits indefinitely.
+#
+############################################################################
+#
+#  Requires:  UNIX, dynamic loading
+#
+############################################################################
+*/
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/time.h>
+
+#include "icall.h"
+
+int fpoll(int argc, descriptor *argv)	/*: await data from file */
+   {
+   FILE *f;
+   int msec, r;
+   fd_set fds;
+   struct timeval tv, *tvp;
+
+   /* check arguments */
+   if (argc < 1)
+      Error(105);
+   if ((IconType(argv[1]) != 'f') || (FileStat(argv[1]) & Fs_Window))
+      ArgError(1, 105);
+   if (!(FileStat(argv[1]) & Fs_Read))
+      ArgError(1, 212);
+   f = FileVal(argv[1]);
+
+   if (argc < 2)
+      msec = -1;
+   else {
+      ArgInteger(2);
+      msec = IntegerVal(argv[2]);
+      }
+
+   /* check for data already in buffer */
+   /* there's no legal way to do this in C; we cheat */
+#if defined(__GLIBC__) && defined(_STDIO_USES_IOSTREAM)	/* new GCC library */
+   if (f->_IO_read_ptr < f->_IO_read_end)
+      RetArg(1);
+#elif defined(__GLIBC__)				/* old GCC library */
+   if (f->__bufp < f->__get_limit)
+      RetArg(1);
+#elif defined(_FSTDIO)					/* new BSD library */
+   if (f->_r > 0)
+      RetArg(1);
+#else							/* old AT&T library */
+   if (f->_cnt > 0)
+      RetArg(1);
+#endif
+
+   /* set up select(2) structure */
+   FD_ZERO(&fds);			/* clear file bits */
+   FD_SET(fileno(f), &fds);		/* set bit of interest */
+
+   /* set up timeout and pointer */
+   if (msec < 0)
+      tvp = NULL;
+   else {
+      tv.tv_sec = msec / 1000;
+      tv.tv_usec = (msec % 1000) * 1000;
+      tvp = &tv;
+      }
+
+   /* poll the file using select(2) */
+   r = select(fileno(f) + 1, &fds, (fd_set*)NULL, (fd_set*)NULL, tvp);
+
+   if (r > 0)
+      RetArg(1);			/* success */
+   else if (r == 0)			
+      Fail;				/* timeout */
+   else
+      ArgError(1, 214);			/* I/O error */
+
+}