From cce61d713461616c3050a0863e826899d92dcbe9 Mon Sep 17 00:00:00 2001
From: Cary R <cygcary@yahoo.com>
Date: Mon, 24 Aug 2009 15:20:42 -0700
Subject: [PATCH] Ignore a zero MCD for $fflush, $fdisplay*, $fwrite* and
 $fstrobe*. (cherry picked from commit
 ed4e2eb046df23d875e43b587bd6107e3982d367)

---
 vpi/sys_display.c | 20 ++++++++++++++++----
 vpi/sys_fileio.c  |  3 +++
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/vpi/sys_display.c b/vpi/sys_display.c
index c0f116290..96cef1789 100644
--- a/vpi/sys_display.c
+++ b/vpi/sys_display.c
@@ -1127,9 +1127,15 @@ static PLI_INT32 sys_display_calltf(PLI_BYTE8 *name)
 	      val.format = vpiIntVal;
 	      vpi_get_value(arg, &val);
 	      fd_mcd = val.value.integer;
+
+		/* If the MCD is zero we have nothing to do so just return. */
+	      if (fd_mcd == 0)  {
+		    vpi_free_object(argv);
+		    return 0;
+	      }
+
 	      if ((! IS_MCD(fd_mcd) && vpi_get_file(fd_mcd) == NULL) ||
-	          ( IS_MCD(fd_mcd) && my_mcd_printf(fd_mcd, "") == EOF) ||
-	          (! fd_mcd)) {
+	          ( IS_MCD(fd_mcd) && my_mcd_printf(fd_mcd, "") == EOF)) {
 		    vpi_printf("WARNING: %s:%d: ", vpi_get_str(vpiFile, callh),
 		               (int)vpi_get(vpiLineNo, callh));
 		    vpi_printf("invalid file descriptor/MCD (0x%x) given "
@@ -1241,9 +1247,15 @@ static PLI_INT32 sys_strobe_calltf(PLI_BYTE8*name)
 	      val.format = vpiIntVal;
 	      vpi_get_value(arg, &val);
 	      fd_mcd = val.value.integer;
+
+		/* If the MCD is zero we have nothing to do so just return. */
+	      if (fd_mcd == 0)  {
+		    vpi_free_object(argv);
+		    return 0;
+	      }
+
 	      if ((! IS_MCD(fd_mcd) && vpi_get_file(fd_mcd) == NULL) ||
-	          ( IS_MCD(fd_mcd) && my_mcd_printf(fd_mcd, "") == EOF) ||
-	          (! fd_mcd))  {
+	          ( IS_MCD(fd_mcd) && my_mcd_printf(fd_mcd, "") == EOF))  {
 		    vpi_printf("WARNING: %s:%d: ", vpi_get_str(vpiFile, callh),
 		               (int)vpi_get(vpiLineNo, callh));
 		    vpi_printf("invalid file descriptor/MCD (0x%x) given "
diff --git a/vpi/sys_fileio.c b/vpi/sys_fileio.c
index f15552d6f..2fccdd49e 100644
--- a/vpi/sys_fileio.c
+++ b/vpi/sys_fileio.c
@@ -270,6 +270,9 @@ static PLI_INT32 sys_fflush_calltf(PLI_BYTE8*name)
       vpi_get_value(arg, &val);
       fd_mcd = val.value.integer;
 
+	/* If the MCD is zero we have nothing to do so just return. */
+      if (fd_mcd == 0) return 0;
+
       if ((! IS_MCD(fd_mcd) && vpi_get_file(fd_mcd) == NULL) ||
           ( IS_MCD(fd_mcd) && vpi_mcd_printf(fd_mcd, str) == EOF) ||
           (! fd_mcd)) {