Answer (1 of 2): You can take a char pointer and then again cast void to that char pointer. args = struct.pack ("iP", len (c), cast (pointer (c), c_void_p).value) err = fcntl.ioctl (eos_fd, request, args) Now to do the same with ctypes, I have one problem. how to cast from (void*) to other types? - C / C++ It is used to convert a pointer of some data type into a pointer of another data type, even if the the data types before and after conversion are different. ; void *ptr = &str; You can just cast back to the string: std::string *pstr = static_cast<std::string *> (ptr); Note that it is on you to verify that ptr actually points to a std::string. In such a case the programmer can use a void pointer to point to the location of the unknown data type. My user-interface uses STL-strings for simple manipulation of user-input. This might complain about not able to convert a LPCSTR to a void*, than add a const_cast<void*>(static_cast<LPCTSTR>(cstr)). config.c:61: warning: cast from pointer to integer of different size config.c:61: warning: assignment makes pointer from integer without a cast AFAIK, casting any pointer type to (void *) need not be typecasted. How to correctly type cast (void*)? The void pointer, also known as the generic pointer, is a special type of pointer that can be pointed at objects of any data type! fatal: Could not read from remote repository. 1) Two possibly multilevel pointers to the same type may be converted between each other, regardless of cv-qualifiers at each level. The void pointer, also known as the generic pointer, is a special type of pointer that can be pointed at objects of any data type! Thanks. * or ->* . From that point on, you are dealing with 32 bits. Void Pointers in C Last updated on July 27, 2020 We have learned in chapter Pointer Basics in C that if a pointer is of type pointer to int or (int *) then it can hold the address of the variable of type int only. A pointer to void simply points to a raw memory location. Cancel. using c way gives "error: cast from 'void*' to 'int' loses precision" Ganado. July 19, 2007, 2:07 pm. An rvalue of type "pointer to cv T," where T is an object type, can be converted to an rvalue of type "pointer to cv void." It basically means: an rvalue T* can be converted to an rvalue void*. static_cast in C++ | Type Casting operators - GeeksforGeeks Unsafe code, pointers to data, and function pointers | Microsoft Docs the comparison is: switch (action): case ("onCollision"){doDestroy(args); break;} case . It would be incorrect, if we assign an address of a float variable to a pointer of type pointer to int. If the size is zero, the value returned depends on the . NAME atof - convert a string to a double. c - Cast void pointer to integer array - TouSu Developer Zone-Ask and ... #include <iostream> using namespace std; int main() { void* ptr; float f = 2.3f; // assign float address to void pointer ptr = &f; cout << "The content of pointer is .