diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7807873..4104cd1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -21,7 +21,7 @@ configure_file (
 #
 if (UNIX)
     set(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -Wall -Wextra -Wno-unused-parameter -fprofile-arcs -ftest-coverage -O0 -pthread -DDEBUG=1")
-    set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -Wall -Wno-unused-parameter -fvisibility=hidden -fvisibility-inlines-hidden -Os -pthread")
+    set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -Wall -Wno-unused-parameter -fvisibility=hidden -Os -pthread")
     set(CMAKE_EXE_LINKER_FLAGS_DEBUG "-lgcov")
 endif() # UNIX
 
diff --git a/platform/platform.h b/platform/platform.h
index 0dc23c8..7a72483 100644
--- a/platform/platform.h
+++ b/platform/platform.h
@@ -5,10 +5,10 @@
 
 /* Sadly we have to have a Windows-ism here */
 #if MSVC
-    typedef uint32_t (__stdcall *PlatformTask)(void *context);
+    typedef unsigned long (__stdcall *PlatformTask)(void *context);
 
     // Use this to define the PlatformTask callback functions to be cross platform
-    #define PlatformTaskFunc(_name) uint32_t __stdcall _name(void *context)
+    #define PlatformTaskFunc(_name) unsigned long __stdcall _name(void *context)
 #else
     typedef void *(*PlatformTask)(void *context);
 
diff --git a/platform/windows.c b/platform/windows.c
index 538d785..2188cdd 100644
--- a/platform/windows.c
+++ b/platform/windows.c
@@ -61,7 +61,7 @@ PlatformTaskFunc(timer_task) {
 
 PlatformStatusCode platform_init(MQTTHandle *handle) {
     handle->platform = (PlatformData *)calloc(1, sizeof(struct _PlatformData));
-    handle->platform->sock = -1;
+    handle->platform->sock = INVALID_SOCKET;
     handle->platform->timer_task = -1;
     if (!handle->platform) {
         return PlatformStatusError;
@@ -257,10 +257,10 @@ PlatformStatusCode platform_write(MQTTHandle *handle, Buffer *buffer) {
 
 PlatformStatusCode platform_disconnect(MQTTHandle *handle) {
     PlatformData *p = handle->platform;
-    if (p->sock >= 0) {
+    if (p->sock != INVALID_SOCKET) {
         closesocket(p->sock);
         WSACleanup();
-        p->sock = -1;
+        p->sock = INVALID_SOCKET;
     }
 
     return PlatformStatusOk;