将.dll导入Qt [英] Importing .dll into Qt

问题描述

我想给我的Qt项目带来一个.dll依赖。

所以我把它添加到我的.pro文件：

  win32 {
 LIBS + = C：\lib\dependency.lib 
 LIBS + = C：\lib \dependency。 dll 
} 
  

然后（我不知道这是否是正确的语法不）

  #include< windows.h> 
 Q_DECL_IMPORT int WINAPI DoSomething（）; 
  

btw .dll看起来像这样：

  #include< windows.h> 
 BOOL APIENTRY DllMain（HANDLE hModule，DWORD ul_reason_for_call，
 LPVOID lpReserved）
 {
 return TRUE; 
} 
 
 externC
 {
 int WINAPI DoSomething（）{return -1; } 
}; 
  

获取错误：未解决的符号？

注意：我没有经验的.dll的.NET的ez pz组件architechture，肯定是一个n00b。

解决方案

LIBS + =语法错误。尝试此操作：

  win32 {
 LIBS + = -LC：/ lib / -ldependency 
} 
  

我也不确定在.pro文件中是否有带驱动器号的绝对路径是一个好主意 - 我通常把依赖关系保存在项目树中的某个位置，并使用相对路径。

编辑：

你的dll中的东西是错误的，即符号不能正确导出。我总是使用由QtCreator提供的模板：

1. 在dll项目中有mydll_global.h头文件， >
   
   

     #ifdef MYDLL_LIB 
    #define MYDLL_EXPORT Q_DECL_EXPORT 
    #else 
    #define MYDLL_EXPORT Q_DECL_IMPORT 
    #endif 
     




2. Dll项目在其专业文件中有DEFINES + = MYDLL_LIB。




3. 导出的类（或仅选定的方法）和自由函数在头文件中标有MYDLL_EXPORT，即

     class MYDLL_EXPORT MyClass {
    
    
    // ... 
    
    
   }; 
     

I want to bring a .dll dependency into my Qt project.

So I added this to my .pro file:

win32 {
LIBS += C:\lib\dependency.lib
LIBS += C:\lib\dependency.dll
}

And then (I don't know if this is the right syntax or not)

#include <windows.h>
Q_DECL_IMPORT int WINAPI DoSomething();

btw the .dll looks something like this:

#include <windows.h>
BOOL APIENTRY DllMain(HANDLE hModule, DWORD ul_reason_for_call, 
                                        LPVOID lpReserved)
{
    return TRUE;
}

extern "C"
{
int WINAPI DoSomething() { return -1; }
};

Getting error: unresolved symbol?

Note: I'm not experienced with .dll's outside of .NET's ez pz assembly architechture, definitely a n00b.

解决方案

Your "LIBS +=" syntax is wrong. Try this:

win32 {
    LIBS += -LC:/lib/ -ldependency
}

I'm also not sure if having absolute paths with drive letter in your .pro file is a good idea - I usually keep the dependencies somewhere in the project tree and use relative path.

EDIT:

I suppose that something is wrong in your dll, i.e. the symbols are not exported correctly. I always use template provided by QtCreator:

1. Inside dll project there is mydll_global.h header with code like that:

   #ifdef MYDLL_LIB
       #define MYDLL_EXPORT Q_DECL_EXPORT
   #else
       #define MYDLL_EXPORT Q_DECL_IMPORT
   #endif
   

2. Dll project has DEFINES += MYDLL_LIB inside it's pro file.

3. Exported class (or only selected methods) and free functions are marked with MYDLL_EXPORT inside header files, i.e.

   class MYDLL_EXPORT MyClass {
   
   
   // ...
   
   
   };
   

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