Converting a pointer into an integer

by

I’d say this is the modern C++ way:

#include <cstdint>
void *p;
auto i = reinterpret_cast<std::uintptr_t>(p);

EDIT:

The correct type to the the Integer

So the right way to store a pointer as an integer is to use the uintptr_t or intptr_t types. (See also in cppreference integer types for C99).

These types are defined in <stdint.h> for C99 and in the namespace std for C++11 in <cstdint> (see integer types for C++).

C++11 (and onwards) Version

#include <cstdint>
std::uintptr_t i;

C++03 Version

extern "C" {
#include <stdint.h>
}

uintptr_t i;

C99 Version

#include <stdint.h>
uintptr_t i;

The correct casting operator

In C there is only one cast and using the C cast in C++ is frowned upon (so don’t use it in C++). In C++ there are different types of casts, but reinterpret_cast is the correct cast for this conversion (see also here).

C++11 Version

auto i = reinterpret_cast<std::uintptr_t>(p);

C++03 Version

uintptr_t i = reinterpret_cast<uintptr_t>(p);

C Version

uintptr_t i = (uintptr_t)p; // C Version

Related Questions

More Related Contents:

  1. Implicit conversion from char** to const char**
  2. Skipping Incompatible Libraries at compile
  3. Convert char to int in C and C++
  4. Using base pointer register in C++ inline asm
  5. Declaring the array size with a non-constant variable
  6. gcc/g++: “No such file or directory”
  7. Array with size 0 [duplicate]
  8. What is the first (int (*)(…))0 vtable entry in the output of g++ -fdump-class-hierarchy?
  9. Is std::string ref-counted in GCC 4.x / C++11?
  10. Why does GCC generate 15-20% faster code if I optimize for size instead of speed?
  11. C++: When (and how) are C++ Global Static Constructors Called?
  12. Why does the enhanced GCC 6 optimizer break practical C++ code?
  13. Reinterpret_cast vs. C-style cast
  14. Precompiled headers with GCC
  15. What is the difference between MinGW, MinGW-w64 and MinGW-builds?
  16. Compiling with -static-libgcc -static-libstdc++ still results in dynamic dependency on libc.so
  17. std::put_time implementation status in GCC?
  18. Overloaded lambdas in C++ and differences between clang and gcc
  19. GNU C++ how to check when -std=c++0x is in effect?
  20. Does a c/c++ compiler optimize constant divisions by power-of-two value into shifts?
  21. Template instantiation details of GCC and MS compilers
  22. Which types on a 64-bit computer are naturally atomic in gnu C and gnu C++? — meaning they have atomic reads, and atomic writes
  23. Why cast a pointer to a float into a pointer to a long, then dereference?
  24. Layout of compiled objects
  25. Does the restrict keyword provide significant benefits in gcc/g++?
  26. std::thread error (thread not member of std)
  27. GCC std::thread not found in namespace std
  28. How to force GCC to assume that a floating-point expression is non-negative?
  29. Where can I find an official reference listing the operation of SSE intrinsic functions?
  30. How can I extend a lexical cast to support enumerated types?

Leave a Comment