diff --git a/progress.cpp b/progress.cpp
index a1ac09f..3fb6cb1 100644
--- a/progress.cpp
+++ b/progress.cpp
@@ -100,7 +100,7 @@ void ProgressBar::print( int perc ) {
 #ifndef _WIN32
     static_cast< ProgressWindow * >( ptr )->setPerc( perc );
 #else
-    PostMessage( ptr, WM_APP, 0, perc );
+    SendMessage( (HWND)ptr, WM_APP, PROGRESS_PERC, perc );
 #endif
 }
 
@@ -108,7 +108,7 @@ void ProgressBar::print( const string &t ) {
 #ifndef _WIN32
     static_cast< ProgressWindow * >( ptr )->setLabel( t );
 #else
-    PostMessage( ptr, WM_APP, 1, ( LPARAM )t.c_str() );
+    SendMessage( (HWND)ptr, WM_APP, PROGRESS_STRING, ( LPARAM )t.c_str() );
 #endif
 }
 
@@ -116,7 +116,7 @@ ProgressBar::~ProgressBar() {
 #ifndef _WIN32
     static_cast< ProgressWindow * >( ptr )->hide();
 #else
-    PostMessageW( ptr, WM_APP, 2, 0 );
+    SendMessage( (HWND)ptr, WM_CLOSE, 0, 0 );
 #endif
 }
 
diff --git a/progress.hpp b/progress.hpp
index c8e4673..332094d 100644
--- a/progress.hpp
+++ b/progress.hpp
@@ -10,6 +10,9 @@ using string = std::wstring;
 using string = std::string;
 #endif
 
+#define PROGRESS_PERC 0x4000
+#define PROGRESS_STRING 0x4001
+
 class ProgressBar {
 public:
 #ifndef GUI
@@ -19,11 +22,7 @@ public:
 #ifndef _WIN32
     ProgressBar( void *pw ) : ptr( pw ){};
 #else
-    ProgressBasr( void *hwnd_in ) {
-        while ( *hwnd_in == nullptr )
-            sleep( 50 );
-        ptr = *hwnd_in;
-    };
+    ProgressBar( void *hwnd ) : ptr( hwnd ){};
 #endif // _WIN32
     ~ProgressBar();
 #endif // GUI