与动态加载的库共享数据（dlopen，dlsym）(Sharing data with a dynamically loaded library (dlopen,dlsym))

与动态加载的库共享数据（dlopen，dlsym）(Sharing data with a dynamically loaded library (dlopen,dlsym))

我的主程序将加载一个名为hello.so的简单动态库

主要的

void* handle = dlopen("./hello.so", RTLD_LAZY);

在main中 ，传递一个名为testing的回调函数（在main.h中的某个地方定义）并从动态库中调用hello（）

typedef void (*callback)(); typedef void (*hello_t)( callback); /* do something */ hello_t hello = (hello_t) dlsym(handle, "hello"); hello(testing);

在动态库中，

#include #include "main.h" extern "C" void hello( void (*fn)() ) { /*do something and then invoke callback function from main */ fn(); }

除了使用回调之外，还有其他方法允许从动态库调用/使用main的函数/数据吗？

My main program would load a simple dynamic library called hello.so

In main

void* handle = dlopen("./hello.so", RTLD_LAZY);

In main , pass a callback function called testing (defined somewhere in main.h) and invoke the hello() from the dynamic library

typedef void (*callback)(); typedef void (*hello_t)( callback); /* do something */ hello_t hello = (hello_t) dlsym(handle, "hello"); hello(testing);

In dynamic library,

#include #include "main.h" extern "C" void hello( void (*fn)() ) { /*do something and then invoke callback function from main */ fn(); }

Are there other ways to allow functions/data of main to be called/used from dynamic library apart from using callbacks?

最满意答案

不，在我看来，这是做这件事的首选方式。 我能想到的任何其他方式都涉及让DLL知道它所链接的程序中的对象，这很可能是不好的做法。

关于数据，只是提醒您虽然没有提出要求，但通常最好的做法是复制需要存储的任何数据，如果它通过库/程序边界传递的话。 如果您使用的数据库的生命周期由程序控制，则可能会陷入完全混乱，反之亦然。

No, this is the preferred way of doing it, in my opinion. Any other way that I can think of involves making the DLL aware of the objects in the program it's linked with, which is most likely bad practice.

Regarding data, just a reminder though you didn't ask, it's usually best practice to copy any data that needs to be stored, if it's passed across library/program boundaries. You can get into a complete mess if you have the library using data whose lifetime is controlled by the program, and vice versa.