diff --git a/lang/cpp/src/callbacks.cpp b/lang/cpp/src/callbacks.cpp
--- a/lang/cpp/src/callbacks.cpp
+++ b/lang/cpp/src/callbacks.cpp
@@ -41,7 +41,9 @@
 #include <cerrno>
 #include <cstring>
 #include <unistd.h>
-#include <stdlib.h>
+#ifndef _MSC_VER
+  #include <unistd.h>
+#endif
 
 static inline gpgme_error_t make_err_from_syserror()
 {
diff --git a/lang/cpp/src/data.h b/lang/cpp/src/data.h
--- a/lang/cpp/src/data.h
+++ b/lang/cpp/src/data.h
@@ -31,6 +31,12 @@
 #include <cstdio> // FILE
 #include <algorithm>
 #include <memory>
+#include <sys/types.h>
+
+#ifdef _MSC_VER
+#  include <BaseTsd.h> // ssize_t on Windows
+#  define ssize_t SSIZE_T
+#endif
 
 namespace GpgME
 {
diff --git a/lang/cpp/src/editinteractor.cpp b/lang/cpp/src/editinteractor.cpp
--- a/lang/cpp/src/editinteractor.cpp
+++ b/lang/cpp/src/editinteractor.cpp
@@ -40,6 +40,11 @@
 # include <unistd.h>
 #endif
 
+#ifdef _MSC_VER
+#  include <BaseTsd.h> // ssize_t on Windows
+#  define ssize_t SSIZE_T
+#endif
+
 #include <cerrno>
 #include <cstring>
 #include <cstdlib>
diff --git a/lang/cpp/src/key.h b/lang/cpp/src/key.h
--- a/lang/cpp/src/key.h
+++ b/lang/cpp/src/key.h
@@ -30,7 +30,7 @@
 #include "gpgmefw.h"
 
 #include <memory>
-#include <sys/time.h>
+#include <ctime>
 
 #include <vector>
 #include <algorithm>