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c++pointersmemory-address

How to take a pointer address as command line argument in C++

I have a C++ code which will take a pointer address as an argument. The code arguments are:

./main 0x7fad529d5000

Now when reading the arguments, this value will be read as a string.

How do I convert the string "0x7fad529d5000" into an address?

Solution

  • Read a hexadecimal from stdin:

    uintptr_t x;
std::cin >> std::hex >> x;

    Read a hexadecimal from string:

    uintptr_t x;
// assuming you used argc / argv and checked argc > 1
std::istringstream sstr( argv[1] );
sstr >> std::hex >> x;

    An alternative would be x = std::stoll( argv[1] ); but there is a cast involved there that I do not quite like (assuming the width of uintptr_t).

    Converting it to a pointer:

    void * p = reinterpret_cast<void *>(x);

    Handle that pointer value with care, because it is unlikely to be valid. (reinterpret_cast is something that should scream "danger!" at you.)