function-pointers

问题 we have a C function in one of the libraries which are loaded in java, which accepts a function pointer function defination as below typedef char int8 typedef unsigned short uint16 uint32 poll_broadcasts(void *(pfn)(int8*,uint16)); In C it is used as below void handle_broadcasts( int8 *broadcast, uint16 length ) uint32 a = poll_broadcasts( (void*(*)(int8*,uint16)) handle_broadcasts ) But when you use Swig to generate JNI wrapper it creates following definition for poll_broadcast public static

问题 C++17 makes noexcept part of a function's type. It also allows implicit conversions from noexcept function pointers to potentially throwing function pointers. void (*ptr_to_noexcept)() noexcept = nullptr; void (*ptr_to_throwing)() = ptr_to_noexcept; // implicit conversion http://eel.is/c++draft/expr.static.cast#7 says that static_cast can perform the inverse of such a conversion. void (*noexcept_again)() noexcept = static_cast<void(*)() noexcept>(ptr_to_throwing); Unfortunately, both GCC and

问题 I'm having getting the above warning and understand it, but just don't know how to fix it. My code is below, but basically what I'm doing is storing a function pointer in a struct, and initializing the struct in another function that I call from my main. The code seems to compile when I use it with a default function (i.e. free()) but not when I use it with the test_func function below. Thoughts? Struct: typedef struct my_struct { my_type **double_pointed; int num; void (*funcp)(void *data);

问题 I have a C++ class that requires a function pointer in it's constructor ( float(*myfunction)(vector<float>*) ) I've already exposed some function pointers to Python. The ideal way to use this class is something like this: import mymodule mymodule.some_class(mymodule.some_function) So I tell Boost about this class like so: class_<SomeClass>("some_class", init<float(*)(vector<float>*)>); But I get: error: no matching function for call to 'register_shared_ptr1(Sample (*)(std::vector<double, std:

问题 I have a C++ class that requires a function pointer in it's constructor ( float(*myfunction)(vector<float>*) ) I've already exposed some function pointers to Python. The ideal way to use this class is something like this: import mymodule mymodule.some_class(mymodule.some_function) So I tell Boost about this class like so: class_<SomeClass>("some_class", init<float(*)(vector<float>*)>); But I get: error: no matching function for call to 'register_shared_ptr1(Sample (*)(std::vector<double, std:

问题 I'm new in programming and learning about pointers in array. I'm a bit confused right now. Have a look at the program below: #include <stdio.h> int fun(); int main() { int num[3][3]={23,32,478,55,0,56,25,13, 80}; printf("%d\n",*(*(num+0)+1)); fun(num); printf("%d\n", *(*(num+0)+1)); *(*(num+0)+0)=23; printf("%d\n",*(*(num+0))); return 0; } int fun(*p) // Compilation error { *(p+0)=0; return 0; } This was the program written in my teacher's notes. Here in the main() function, in the printf()

问题 I'm new in programming and learning about pointers in array. I'm a bit confused right now. Have a look at the program below: #include <stdio.h> int fun(); int main() { int num[3][3]={23,32,478,55,0,56,25,13, 80}; printf("%d\n",*(*(num+0)+1)); fun(num); printf("%d\n", *(*(num+0)+1)); *(*(num+0)+0)=23; printf("%d\n",*(*(num+0))); return 0; } int fun(*p) // Compilation error { *(p+0)=0; return 0; } This was the program written in my teacher's notes. Here in the main() function, in the printf()

问题 I have a C header with: typedef struct { <normal members> void (*cb_func)(glp_tree *T, void *info); void *cb_info; <normal members> } glp_iocp; Currently, in my pxd file: ctypedef struct IntOptCP "glp_iocp": <normal members> int out_dly # mip.out_dly (milliseconds) #void (*cb_func)(Tree* tree, void* info) # mip.cb_func #void* cb_info # mip.cb_info <normal members> In a pyx file, at some point, I do (essentially): cdef class MyClass: IntOptCP _iocp <__cintit__ and the like> def some_method

问题 I have a C header with: typedef struct { <normal members> void (*cb_func)(glp_tree *T, void *info); void *cb_info; <normal members> } glp_iocp; Currently, in my pxd file: ctypedef struct IntOptCP "glp_iocp": <normal members> int out_dly # mip.out_dly (milliseconds) #void (*cb_func)(Tree* tree, void* info) # mip.cb_func #void* cb_info # mip.cb_info <normal members> In a pyx file, at some point, I do (essentially): cdef class MyClass: IntOptCP _iocp <__cintit__ and the like> def some_method

问题 I'm writing a delegate class but it fails to take const member functions. Here is a test case : class foo { public: void MemberFunction() { printf("non const member function\n"); } void ConstMemberFunction() const { printf("const member function\n"); } }; template <class C, void (C::*Function)()> void Call(C* instance) { (instance->*Function)(); } int main (int argc, char** argv) { foo bar; Call<foo,&foo::MemberFunction>(&bar); Call<foo,&foo::ConstMemberFunction>(&bar); } Now the compiler