diff --git a/GLPI-AgentMonitor.cpp b/GLPI-AgentMonitor.cpp
index d191a29..df21e2b 100644
--- a/GLPI-AgentMonitor.cpp
+++ b/GLPI-AgentMonitor.cpp
@@ -215,7 +215,7 @@ VOID CloseWinHttpRequest(HINTERNET hInternet) {
 }
 
 // Callback called by the asynchronous WinHTTP request
-VOID WinHttpCallback(HINTERNET hInternet, DWORD_PTR dwContext, DWORD dwInternetStatus, LPVOID lpvStatusInfo, DWORD dwStatusInfoLength)
+VOID CALLBACK WinHttpCallback(HINTERNET hInternet, DWORD_PTR dwContext, DWORD dwInternetStatus, LPVOID lpvStatusInfo, DWORD dwStatusInfoLength)
 {
     switch (dwInternetStatus)
     {