diff --git a/include/verilated_vcd_c.cpp b/include/verilated_vcd_c.cpp
index 57bd4cf6f..9c442d692 100644
--- a/include/verilated_vcd_c.cpp
+++ b/include/verilated_vcd_c.cpp
@@ -260,10 +260,10 @@ void VerilatedVcd::bufferFlush () {
     if (VL_UNLIKELY(!isOpen())) return;
     char* wp = m_wrBufp;
     while (1) {
-	size_t remaining = (m_writep - wp);
+	ssize_t remaining = (m_writep - wp);
 	if (remaining==0) break;
 	errno = 0;
-	int got = write (m_fd, wp, remaining);
+	ssize_t got = write (m_fd, wp, remaining);
 	if (got>0) {
 	    wp += got;
 	    m_wroteBytes += got;
diff --git a/include/verilatedos.h b/include/verilatedos.h
index 07c01ec2e..124004d6b 100644
--- a/include/verilatedos.h
+++ b/include/verilatedos.h
@@ -146,6 +146,14 @@ typedef unsigned __int32	vluint32_t;	///< 32-bit unsigned type
 typedef signed   __int64	vlsint64_t;	///< 64-bit signed type
 typedef unsigned __int64	vluint64_t;	///< 64-bit unsigned type
 
+# ifndef _SSIZE_T_DEFINED
+#  ifdef  _WIN64
+typedef signed   __int64        ssize_t;        ///< signed size_t; returned from read()
+#  else
+typedef signed   __int32        ssize_t;        ///< signed size_t; returned from read()
+#  endif
+# endif
+
 #else // Linux or compliant Unix flavors, -m64
 
 # include <stdint.h>	// Linux and most flavors
diff --git a/test_regress/t/t_dpi_context_c.cpp b/test_regress/t/t_dpi_context_c.cpp
index 075c77ffd..3610be8b4 100644
--- a/test_regress/t/t_dpi_context_c.cpp
+++ b/test_regress/t/t_dpi_context_c.cpp
@@ -14,7 +14,7 @@
 //*************************************************************************
 
 #include <cstdio>
-#include <svdpi.h>
+#include "svdpi.h"
 
 //======================================================================
 
diff --git a/test_regress/t/t_dpi_display_c.cpp b/test_regress/t/t_dpi_display_c.cpp
index 914782add..94dbd91a2 100644
--- a/test_regress/t/t_dpi_display_c.cpp
+++ b/test_regress/t/t_dpi_display_c.cpp
@@ -14,7 +14,7 @@
 //*************************************************************************
 
 #include <cstdio>
-#include <svdpi.h>
+#include "svdpi.h"
 
 //======================================================================
 
diff --git a/test_regress/t/t_dpi_export_c.cpp b/test_regress/t/t_dpi_export_c.cpp
index b9cb572b7..e6d16f344 100644
--- a/test_regress/t/t_dpi_export_c.cpp
+++ b/test_regress/t/t_dpi_export_c.cpp
@@ -14,8 +14,8 @@
 //*************************************************************************
 
 #include <cstdio>
-#include <svdpi.h>
 #include <cstring>
+#include "svdpi.h"
 
 #ifdef _WIN32
 # define T_PRI64 "I64"
diff --git a/test_regress/t/t_dpi_import_c.cpp b/test_regress/t/t_dpi_import_c.cpp
index 053ab3f40..70d95cfa8 100644
--- a/test_regress/t/t_dpi_import_c.cpp
+++ b/test_regress/t/t_dpi_import_c.cpp
@@ -15,7 +15,7 @@
 
 #include <cstdio>
 #include <cstring>
-#include <svdpi.h>
+#include "svdpi.h"
 
 //======================================================================
 
diff --git a/test_regress/t/t_dpi_sys_c.cpp b/test_regress/t/t_dpi_sys_c.cpp
index da380e7eb..b7473d15e 100644
--- a/test_regress/t/t_dpi_sys_c.cpp
+++ b/test_regress/t/t_dpi_sys_c.cpp
@@ -14,7 +14,7 @@
 //*************************************************************************
 
 #include <cstdio>
-#include <svdpi.h>
+#include "svdpi.h"
 
 //======================================================================
 
diff --git a/test_regress/t/t_flag_ldflags_c.cpp b/test_regress/t/t_flag_ldflags_c.cpp
index 2cb0db795..ebb86803e 100644
--- a/test_regress/t/t_flag_ldflags_c.cpp
+++ b/test_regress/t/t_flag_ldflags_c.cpp
@@ -14,7 +14,7 @@
 //*************************************************************************
 
 #include <cstdio>
-#include <svdpi.h>
+#include "svdpi.h"
 
 //======================================================================