What decides the sizeof an integer?

by

Taken from http://en.wikipedia.org/wiki/64-bit (under 64-bit data models)

There are various models, Microsoft decided that sizeof(int) == 4, some (a few) others didn’t.

HAL Computer Systems port of Solaris to SPARC64 and Unicos seem to be the only ones where sizeof(int) == 8. They are called ILP64 and SILP64 models.

The true “war” was for sizeof(long), where Microsoft decided for sizeof(long) == 4 (LLP64) while nearly everyone else decided for sizeof(long) == 8 (LP64).

Note that in truth it’s the compiler that “decides” which model to use, but as written in the wiki

Note that a programming model is a choice made on a per-compiler basis, and several can coexist on the same OS. However, the programming model chosen as the primary model for the OS API typically dominates.

More Related Contents:

  1. What’s sizeof(size_t) on 32-bit vs the various 64-bit data models?
  2. Size of pid_t, uid_t, gid_t on Linux
  3. Logic behind sizeof operator [duplicate]
  4. What does sizeof(&array) return?
  5. Why does a C-Array have a wrong sizeof() value when it’s passed to a function? [duplicate]
  6. newbie questions about malloc and sizeof
  7. Using sizeof with a dynamically allocated array
  8. How does an uninitiliazed variable get a garbage value?
  9. Fast computing of log2 for 64-bit integers
  10. What do R_X86_64_32S and R_X86_64_64 relocation mean?
  11. C compiler asserts – how to implement?
  12. What does ‘sizeof (function name)’ return?
  13. In C, why is sizeof(char) 1, when ‘a’ is an int?
  14. How can I print the result of sizeof() at compile time in C?
  15. x86_64 ASM – maximum bytes for an instruction?
  16. Why is (sizeof(int) > -1) false? [duplicate]
  17. C left shift on 64 bits fail
  18. C compiler for Windows? [closed]
  19. Using sizeof() on malloc’d memory [duplicate]
  20. Why do I get a warning every time I use malloc?
  21. Which C99 features are available in the MS Visual Studio compiler?
  22. sizeof single struct member in C
  23. Implementation of sizeof operator
  24. Is the operand of `sizeof` evaluated with a VLA?
  25. c++ sizeof() of a class with functions
  26. Is there a C compiler that targets the 8086? [closed]
  27. Reliably determine the number of elements in an array
  28. Statically link ncurses to program
  29. C -> sizeof string is always 8
  30. library not found for -lrt with QtCreator [mac os]

Leave a Comment