Merge pull request #5 from nitro44x/FreeLibrary_retcode

Fixed error code checking for Win32 systems

Author: drdanz

src/SharedLibrary.cpp

@@ -55,55 +55,63 @@ bool SharedLibrary::open(const char *filename)
     close();
 #if defined(_WIN32)
     mPriv->implementation = (void*)LoadLibrary(filename);
-    LPTSTR msg = nullptr;
-    FormatMessage(
-       FORMAT_MESSAGE_FROM_SYSTEM |FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_IGNORE_INSERTS,
-       nullptr, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
-       (LPTSTR)&msg, 0, nullptr);
+    if (!mPriv->implementation) {
+        LPTSTR msg = nullptr;
+        FormatMessage(
+            FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_IGNORE_INSERTS,
+            nullptr, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+            (LPTSTR)&msg, 0, nullptr);
 
-    if(msg != nullptr) {
-        mPriv->err_message = std::string(msg);
-       // release memory allocated by FormatMessage()
-       LocalFree(msg); msg = nullptr;
+        if (msg != nullptr) {
+            mPriv->err_message = std::string(msg);
+            // release memory allocated by FormatMessage()
+            LocalFree(msg); msg = nullptr;
+        }
     }
     return (mPriv->implementation != nullptr);
 #else
     mPriv->implementation = dlopen(filename, RTLD_LAZY);
-    char* msg = dlerror();
-    if(msg)
-        mPriv->err_message = msg;
+    if (!mPriv->implementation) {
+        char* msg = dlerror();
+        if (msg)
+            mPriv->err_message = msg;
+    }
     return mPriv->implementation != nullptr;
 #endif
 }
 
 bool SharedLibrary::close() {
-    int result = 0;
+    bool error = false;
     if (mPriv->implementation != nullptr) {
 #if defined(WIN32)
-        result = FreeLibrary((HINSTANCE)mPriv->implementation);
-        LPTSTR msg = nullptr;
-        FormatMessage(
-           FORMAT_MESSAGE_FROM_SYSTEM |FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_IGNORE_INSERTS,
-           nullptr, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
-           (LPTSTR)&msg, 0, nullptr);
-
-        if(msg != nullptr) {
-            mPriv->err_message = std::string(msg);
-            // release memory allocated by FormatMessage()
-            LocalFree(msg); msg = nullptr;
+        auto result = FreeLibrary((HINSTANCE)mPriv->implementation);
+        if (!result) {
+            error = true;
+            LPTSTR msg = nullptr;
+            FormatMessage(
+                FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_IGNORE_INSERTS,
+                nullptr, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+                (LPTSTR)&msg, 0, nullptr);
+
+            if (msg != nullptr) {
+                mPriv->err_message = std::string(msg);
+                // release memory allocated by FormatMessage()
+                LocalFree(msg); msg = nullptr;
+            }
         }
 #else
-        result = dlclose(mPriv->implementation);
+        auto result = dlclose(mPriv->implementation);
         if (result != 0) {
-        char* msg = dlerror();
-        if(msg)
-            mPriv->err_message = msg;
+            error = true;
+            char* msg = dlerror();
+            if(msg)
+                mPriv->err_message = msg;
         }
 #endif
         mPriv->implementation = nullptr;
 
     }
-    return (result == 0);
+    return error;
 }
 
 std::string SharedLibrary::error()

src/shlibpp/SharedLibraryClassApi.h

@@ -40,7 +40,7 @@ extern "C" {
 
         using createFn_t = void*(*)();
         using destroyFn_t = void(*)(void*);
-        using getFn_t = int32_t(*)(char*, size_t);
+        using getFn_t = size_t(*)(char*, size_t);
 
         createFn_t create;        // Instantiate a plugin object.
         destroyFn_t destroy;      // Destroy a plugin object.
@@ -114,24 +114,24 @@ constexpr int32_t SHLIBPP_DEFAULT_SYSTEM_VERSION = 5;
         } \
     } \
     \
-    SHLIBPP_SHARED_CLASS_FN int32_t factoryname ## _getVersion (char* ver, size_t len) \
+    SHLIBPP_SHARED_CLASS_FN size_t factoryname ## _getVersion (char* ver, size_t len) \
     { \
         return 0; \
     } \
     \
-    SHLIBPP_SHARED_CLASS_FN int32_t factoryname ## _getAbi (char* abi, size_t len) \
+    SHLIBPP_SHARED_CLASS_FN size_t factoryname ## _getAbi (char* abi, size_t len) \
     { \
         return 0; \
     } \
     \
-    SHLIBPP_SHARED_CLASS_FN int32_t factoryname ## _getClassName (char* name, size_t len) \
+    SHLIBPP_SHARED_CLASS_FN size_t factoryname ## _getClassName (char* name, size_t len) \
     { \
         char cname[] = # classname; \
         strncpy(name, cname, len); \
         return strlen(cname) + 1; \
     } \
     \
-    SHLIBPP_SHARED_CLASS_FN int32_t factoryname ## _getBaseClassName (char* name, size_t len) \
+    SHLIBPP_SHARED_CLASS_FN size_t factoryname ## _getBaseClassName (char* name, size_t len) \
     { \
         char cname[] = # basename; \
         strncpy(name, cname, len); \

src/shlibpp/SharedLibraryFactory.h

@@ -14,7 +14,7 @@
 
 namespace shlibpp {
 
-class SharedLibraryClassApi;
+struct SharedLibraryClassApi;
 
 /**
  * A wrapper for a named factory method in a named shared library.