function-pointers | 易学教程

C Pass arguments as void-pointer-list to imported function from LoadLibrary()

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问题 The problem I have is that I want to create a generic command line application that can be used to load a library DLL and then call a function in the library DLL. The function name is specified on the command line with the arguments also provided on the utility command line. I can access the external function from a DLL dynamically loaded using the LoadLibrary() function. Once the library is loaded I can obtain a pointer to the function using GetProcAddress() I want to call the function with

C Pass arguments as void-pointer-list to imported function from LoadLibrary()

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The problem I have is that I want to create a generic command line application that can be used to load a library DLL and then call a function in the library DLL. The function name is specified on the command line with the arguments also provided on the utility command line. I can access the external function from a DLL dynamically loaded using the LoadLibrary() function. Once the library is loaded I can obtain a pointer to the function using GetProcAddress() I want to call the function with the arguments specified on the command line. Can I pass a void-pointer-list to the function-pointer

Writing a function pointer in c

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问题 I was recently reading a code, and found that a function pointer is written as : int (*fn_pointer ( this_args ))( this_args ) I usually encounter a function pointer like this : return_type (*fn_pointer ) (arguments); Similar thing is discussed here: // this is a function called functionFactory which receives parameter n // and returns a pointer to another function which receives two ints // and it returns another int int (*functionFactory(int n))(int, int) { printf("Got parameter %d", n); int

Expression SFINAE to overload on type of passed function pointer

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问题 In this example a function is passed to an implicitly instantiated function template. // Function that will be passed as argument int foo() { return 0; } // Function template to call passed function template<typename F> int call(F f) { return f(); } template<typename F, typename A> int call(F f, A a) { return f(a); } int a = call(foo); We can break this code by adding an overload for foo() . int foo(int i) { return 0; } The name " foo " is now ambiguous and the example will no longer compile.

Convert lambda with capture clause stored in std::function to raw function pointer

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Since my last recent question was unfortunately worded and resulted in a solution to another problem then mine, here I will try to formulate my actual problem in a clear way. Before we start, as a sidenote, I am integrating the Javascript Engine V8 into my C++ application. That's where all the types in the example come from. And that's also the reason for the fact that I need a raw function pointer in the end. But I elaborate on this below. From inside a class I need to pass a lambda expression with the capture clause [=] as parameter of the type std::function to another function and cast it

Representing NULL Function Pointers to C Functions in Swift

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Consider the private-yet-sort-of-documented Cocoa C functions _NSLogCStringFunction() and _NSSetLogCStringFunction() . _NSLogCStringFunction() returns a function pointer to the C function used by the Objective-C runtime behind-the-scenes for NSLog() , and _NSSetLogCStringFunction() allows developers to specify their own C function for logging. More information on both of these functions can be found in this Stack Overflow question and this WebObjects support article . In C, I can pass in a NULL function pointer to _NSSetLogCStringFunction() : extern void _NSSetLogCStringFunction(void(*)(const

Incrementing function pointers

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I just learned about function pointers (pointers pointing at the adress where where the machine code of a function is stored). This made me think about machine code and how it is stored in memory. Is the machine code stored consecutively in memory, so that it is possible to "manually" increase the pointer until it points to the following/previous function? Is this, what a debugger does? He lets me "see" where the program counter is pointing in the machine code? Conclusion: one can program with function pointers a primitive debugger? Did I understand this right, or am I way off? BlueRaja -

Convert lambda with capture clause stored in std::function to raw function pointer

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问题 Since my last recent question was unfortunately worded and resulted in a solution to another problem then mine, here I will try to formulate my actual problem in a clear way. Before we start, as a sidenote, I am integrating the Javascript Engine V8 into my C++ application. That's where all the types in the example come from. And that's also the reason for the fact that I need a raw function pointer in the end. But I elaborate on this below. From inside a class I need to pass a lambda

Representing NULL Function Pointers to C Functions in Swift

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问题 Consider the private-yet-sort-of-documented Cocoa C functions _NSLogCStringFunction() and _NSSetLogCStringFunction() . _NSLogCStringFunction() returns a function pointer to the C function used by the Objective-C runtime behind-the-scenes for NSLog() , and _NSSetLogCStringFunction() allows developers to specify their own C function for logging. More information on both of these functions can be found in this Stack Overflow question and this WebObjects support article. In C, I can pass in a

Reference to member function? [duplicate]

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This question already has an answer here: Why doesn't reference-to-member exist in C++? 1 answer I recently find out that there is a reference-to-function concept in C++ :). So as there are pointer-to-function and pointer-to-member-function different types. The question arises. Is there a "reference-to-member-function" concept? I tried to compile the following code, but GCC 3.4.6 gives an error. #include <iostream> using namespace std; class A { public: virtual void Af() const { cout << "A::Af()" << endl; } }; int main() { typedef void (A::& MemFnc)() const; MemFnc mf = &A::Af; A a; (a.*mf)();