Merge pull request #6 from tocola/dev

feat: dlerror on unix && getVariable() returns a ref to <T>

CMakeLists.txt

@@ -60,8 +60,8 @@ endif(WITH_TESTS)
 set(CPACK_PACKAGE_NAME "DyLib")
 set(CPACK_PACKAGE_VENDOR "Martin Olivier")
 set(CPACK_PACKAGE_VERSION_MAJOR "1")
-set(CPACK_PACKAGE_VERSION_MINOR "5")
-set(CPACK_PACKAGE_VERSION_PATCH "1")
+set(CPACK_PACKAGE_VERSION_MINOR "6")
+set(CPACK_PACKAGE_VERSION_PATCH "0")
 set(CPACK_PACKAGE_VERSION "${CPACK_PACKAGE_VERSION_MAJOR}.${CPACK_PACKAGE_VERSION_MINOR}.${CPACK_PACKAGE_VERSION_PATCH}")
 set(CPACK_PACKAGE_DESCRIPTION "Cross-platform Dynamic Library Loader for C++")
 set(CPACK_DEBIAN_PACKAGE_NAME "${CPACK_PACKAGE_NAME}")

DyLib.hpp

@@ -2,7 +2,7 @@
  * \file DyLib.hpp
  * \brief Cross-platform Dynamic Library Loader
  * \author Martin Olivier
- * \version 1.5.1
+ * \version 1.6.0
  * 
  * MIT License
  * Copyright (c) 2021 Martin Olivier
@@ -29,6 +29,14 @@ class DyLib
     {
         return LoadLibrary(TEXT(path));
     }
+    static std::string getHandleError(const std::string &name)
+    {
+        return "error while loading dynamic library : " + name;
+    }
+    static std::string getSymbolError(const std::string &name)
+    {
+        return "error while loading symbol : " + name;
+    }
     FARPROC getSymbol(const char *name) const noexcept
     {
         return GetProcAddress(m_handle, name);
@@ -43,6 +51,20 @@ class DyLib
     {
         return dlopen(path, RTLD_NOW | RTLD_LOCAL);
     }
+    static std::string getHandleError(const std::string &name)
+    {
+        auto err = dlerror();
+        if (!err)
+            return "error while loading dynamic library : " + name;
+        return err;
+    }
+    static std::string getSymbolError(const std::string &name)
+    {
+        auto err = dlerror();
+        if (!err)
+            return "error while loading symbol : " + name;
+        return err;
+    }
     void *getSymbol(const char *name) const noexcept
     {
         return dlsym(m_handle, name);
@@ -77,7 +99,7 @@ class DyLib
     };
 
     /**
-     *  This exception is thrown when the library failed to load
+     *  This exception is thrown when the library failed to load 
      *  or the library encountered symbol resolution issues
      *
      *  @param message error message
@@ -89,7 +111,7 @@ class DyLib
     };
 
     /**
-     *  This exception is thrown when the library failed to load a symbol.
+     *  This exception is thrown when the library failed to load a symbol. 
      *  This usually happens when you forgot to mark a library function or variable as extern "C"
      *
      *  @param message error message
@@ -104,6 +126,7 @@ class DyLib
      *  Creates a dynamic library object
      */
     constexpr DyLib() noexcept = default;
+
     DyLib(const DyLib&) = delete;
     DyLib& operator=(const DyLib&) = delete;
 
@@ -144,16 +167,11 @@ class DyLib
         open(path.c_str());
     }
 
-    DyLib(std::string &&path, const char *ext)
+    DyLib(std::string path, const char *ext)
     {
         open(std::move(path), ext);
     }
 
-    DyLib(const std::string &path, const char *ext)
-    {
-        open(path, ext);
-    }
-
     ~DyLib()
     {
         close();
@@ -170,38 +188,26 @@ class DyLib
     {
         close();
         if (!path)
-            throw handle_error("error while loading the dynamic library : (nullptr)");
+            throw handle_error(getHandleError("(nullptr)"));
         m_handle = openLib(path);
         if (!m_handle)
-            throw handle_error("error while loading the dynamic library : " + std::string(path));
+            throw handle_error(getHandleError(path));
     }
 
     void open(const std::string &path)
     {
         open(path.c_str());
     }
 
-    void open(std::string &&path, const char *ext)
+    void open(std::string path, const char *ext)
     {
         close();
         if (!ext)
-            throw handle_error("bad extension name : (nullptr)");
+            throw handle_error(getHandleError("bad extension name : (nullptr)"));
         path += ext;
         m_handle = openLib(path.c_str());
         if (!m_handle)
-            throw handle_error("error while loading the dynamic library : " + path);
-    }
-
-    void open(const std::string &path, const char *ext)
-    {
-        close();
-        if (!ext)
-            throw handle_error("bad extension name : (nullptr)");
-        std::string path_ext(path);
-        path_ext += ext;
-        m_handle = openLib(path_ext.c_str());
-        if (!m_handle)
-            throw handle_error("error while loading the dynamic library : " + path_ext);
+            throw handle_error(getHandleError(path));
     }
 
     /**
@@ -219,10 +225,10 @@ class DyLib
         if (!m_handle)
             throw handle_error("error : no dynamic library loaded");
         if (!name)
-            throw symbol_error("error while loading function : (nullptr)");
+            throw symbol_error(getSymbolError("(nullptr)"));
         auto sym = getSymbol(name);
         if (!sym)
-            throw symbol_error("error while loading function : " + std::string(name));
+            throw symbol_error(getSymbolError(name));
         return reinterpret_cast<T *>(sym);
     }
 
@@ -241,20 +247,20 @@ class DyLib
      *  @returns global variable of type <T>
      */
     template<typename T>
-    T getVariable(const char *name) const
+    T &getVariable(const char *name) const
     {
         if (!m_handle)
             throw handle_error("error : no dynamic library loaded");
         if (!name)
-            throw symbol_error("error while loading global variable : (nullptr)");
+            throw symbol_error(getSymbolError("(nullptr)"));
         auto sym = getSymbol(name);
         if (!sym)
-            throw symbol_error("error while loading global variable : " + std::string(name));
+            throw symbol_error(getSymbolError(name));
         return *reinterpret_cast<T *>(sym);
     }
 
     template<typename T>
-    T getVariable(const std::string &name) const
+    T &getVariable(const std::string &name) const
     {
         return getVariable<T>(name.c_str());
     }

README.md

@@ -1,5 +1,5 @@
 # DyLib - Dynamic Library Loader for C++  
-[![DyLib](https://img.shields.io/badge/DyLib-v1.5.1-blue.svg)](https://github.com/tocola/DyLib/releases/tag/v1.5.1)
+[![DyLib](https://img.shields.io/badge/DyLib-v1.6.0-blue.svg)](https://github.com/tocola/DyLib/releases/tag/v1.6.0)
 [![MIT license](https://img.shields.io/badge/License-MIT-orange.svg)](https://github.com/tocola/DyLib/blob/main/LICENSE)
 [![CPP Version](https://img.shields.io/badge/C++-11/14/17/20-darkgreen.svg)](https://isocpp.org/)
 
@@ -10,7 +10,7 @@
 [![workflow](https://github.com/tocola/DyLib/actions/workflows/unit_tests.yml/badge.svg)](https://github.com/tocola/DyLib/actions/workflows/unit_tests.yml)
 [![codecov](https://codecov.io/gh/tocola/DyLib/branch/main/graph/badge.svg?token=4V6A9B7PII)](https://codecov.io/gh/tocola/DyLib)
 
-[![GitHub download](https://img.shields.io/github/downloads/tocola/DyLib/total?style=for-the-badge)](https://github.com/tocola/DyLib/releases/download/v1.5.1/DyLib.hpp)
+[![GitHub download](https://img.shields.io/github/downloads/tocola/DyLib/total?style=for-the-badge)](https://github.com/tocola/DyLib/releases/download/v1.6.0/DyLib.hpp)
 
 The goal of this C++ Library is to load dynamic libraries (.so, .dll, .dylib) and access its functions and global variables at runtime.
 
@@ -19,7 +19,7 @@ Works on `Linux`, `Windows`, `MacOS`
 
 # Installation
 
-Click [HERE](https://github.com/tocola/DyLib/releases/download/v1.5.1/DyLib.hpp) to download the DyLib header file  
+Click [HERE](https://github.com/tocola/DyLib/releases/download/v1.6.0/DyLib.hpp) to download the DyLib header file  
 `Don't forget to put a star on the project 🌟`
 
 # Documentation
@@ -120,7 +120,7 @@ Lets write some functions in our future dynamic library :
 
 extern "C" {
     double pi_value = 3.14159;
-    void *ptr = nullptr;
+    void *ptr = (void *)1;
 
     double adder(double a, double b)
     {
@@ -159,9 +159,9 @@ int main()
         double pi_value = lib.getVariable<double>("pi_value");
         std::cout << pi_value << std::endl;
 
-        void *ptr = lib.getVariable<void *>("ptr");
-        if (ptr == nullptr)
-            std::cout << "nullptr" << std::endl;
+        auto &ptr = lib.getVariable<void *>("ptr");
+        if (ptr == (void *)1)
+            std::cout << "1" << std::endl;
     }
     catch (const DyLib::exception &e) {
         std::cerr << e.what() << std::endl;
@@ -180,5 +180,5 @@ Output :
 15
 Hello!
 3.14159
-nullptr
+1
 ```

test/myDynLib.cpp

@@ -2,7 +2,7 @@
 
 extern "C" {
     double pi_value = 3.14159;
-    void *ptr = nullptr;
+    void *ptr = (void *)1;
 
     double adder(double a, double b)
     {

test/tests.cpp

@@ -45,7 +45,7 @@ TEST(exemple, exemple_test)
         EXPECT_EQ(pi_value, 3.14159);
 
         void *ptr = lib.getVariable<void *>("ptr");
-        EXPECT_EQ(ptr, nullptr);
+        EXPECT_EQ(ptr, (void *)1);
     }
     catch (const DyLib::exception &) {
         EXPECT_EQ(true, false);
@@ -59,7 +59,8 @@ TEST(ctor, bad_library)
         EXPECT_EQ(true, false);
     }
     catch (const DyLib::exception &e) {
-        EXPECT_EQ(std::string(e.what()), "error while loading the dynamic library : ./null.so");
+        e.what();
+        EXPECT_EQ(true, true);
     }
 }
 
@@ -132,6 +133,28 @@ TEST(getVariable, bad_symbol)
     }
 }
 
+TEST(getVariable, alter_variables)
+{
+    try {
+        DyLib lib(std::string("./dynlib"), DyLib::extension);
+        DyLib other(std::move(lib));
+        auto &pi = other.getVariable<double>("pi_value");
+        EXPECT_EQ(pi, 3.14159);
+        pi = 123;
+        auto &pi1 = other.getVariable<double>("pi_value");
+        EXPECT_EQ(pi1, 123);
+
+        auto &ptr = other.getVariable<void *>("ptr");
+        EXPECT_EQ(ptr, (void *)1);
+        ptr = &lib;
+        auto &ptr1 = other.getVariable<void *>("ptr");
+        EXPECT_EQ(ptr1, &lib);
+    }
+    catch (const DyLib::handle_error &) {
+        EXPECT_EQ(true, false);
+    }
+}
+
 TEST(bad_arguments, null_pointer)
 {
     try {
@@ -198,7 +221,7 @@ TEST(std_move, basic_test)
         EXPECT_EQ(pi, 3.14159);
         lib = std::move(other);
         auto ptr = lib.getVariable<void *>("ptr");
-        EXPECT_EQ(ptr, nullptr);
+        EXPECT_EQ(ptr, (void *)1);
         other.getVariable<double>("pi_value");
         EXPECT_EQ(true, false);
     }