Ticket #4422: dlerr.win.2.patch

libs/libmyth/compat.h

@@ -17 +17 @@
 #include <ws2tcpip.h>
 #define setsockopt(a, b, c, d, e) setsockopt(a, b, c, (const char*)(d), e)
 #undef close
+#include <stdio.h>  // for snprintf(), used by inline dlerror()
 #else
 #include <sys/time.h>     // Mac OS X needs this before sys/resource
 #include <sys/resource.h> // for setpriority
@@ -189 +190 @@
 #define dlopen(x, y) LoadLibraryA((x))
 #define dlclose(x) !FreeLibrary((HMODULE)(x))
 #define dlsym(x, y) GetProcAddress((HMODULE)(x), (y))
-#define dlerror GetLastError
+//
+//#define dlerror()  ""
+inline const char *dlerror(void)
+{
+  #define DLERR_MAX 512
+    static char errStr[DLERR_MAX];
+    DWORD       errCode = GetLastError();
+
+    if (!FormatMessage (FORMAT_MESSAGE_FROM_SYSTEM |
+                        FORMAT_MESSAGE_IGNORE_INSERTS |
+                        FORMAT_MESSAGE_MAX_WIDTH_MASK,
+                        NULL, errCode,
+                        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+                        errStr, DLERR_MAX - 1, NULL))
+        snprintf(errStr, DLERR_MAX - 1,
+                 "dlopen()/dlsym() caused error %d", errCode);
+
+    return errStr;
+}
 #endif // USING_MINGW
 
 #ifdef USING_MINGW