sizeof(struct) returns unexpected value

by

It’s padding the struct to fit an 8-byte boundary. So it actually is taking 40 bytes in memory – sizeof is returning the correct value.

If you want it to only take 33 bytes then specify the packed attribute:

struct region
{
public:
    long long int x;
    long long int y;
    long long int width;
    long long int height;
    unsigned char scale;
} __attribute__ ((packed));

More Related Contents:

  1. Structure size so big, need optimization
  2. Error when building a C++ program for the second time [closed]
  3. Why isn’t sizeof for a struct equal to the sum of sizeof of each member?
  4. std::stoi doesn’t exist in g++ 4.6.1 on MinGW
  5. Compile a DLL in C/C++, then call it from another program
  6. Is the size of a struct required to be an exact multiple of the alignment of that struct?
  7. What is the difference between MinGW, MinGW-w64 and MinGW-builds?
  8. Linking to MSVC DLL from MinGW
  9. How to enable experimental C++11 concurrency features in MinGW?
  10. GCC C++ pow accuracy
  11. How to update GCC in MinGW on Windows?
  12. Compiling a Win32 GUI app (without a console) using MinGW and Eclipse
  13. Static and Dynamic/Shared Linking with MinGW
  14. Difference between ‘struct’ and ‘typedef struct’ in C++?
  15. How exactly does __attribute__((constructor)) work?
  16. Why is my program slow when looping over exactly 8192 elements?
  17. Sizeof string literal
  18. GCC STL bound checking
  19. Structure of a C++ Object in Memory Vs a Struct
  20. undefined reference to `__stack_chk_fail’
  21. SetJmp/LongJmp: Why is this throwing a segfault?
  22. What happened to the “aggregate or union type that includes one of the aforementioned types” strict aliasing rule?
  23. Force C++ structure to pack tightly
  24. MinGW GCC: “Unknown conversion type character ‘h'” (snprintf)
  25. What does -fPIC mean when building a shared library?
  26. Multiple “could not be resolved” problems using Eclipse with minGW
  27. Purpose of struct, typedef struct, in C++
  28. c++11 std::async doesn’t work in mingw
  29. Undefined reference to process(std::__cxx11::basic_string … ) when compiling affdex linux sample applications
  30. Variable Sized Struct C++

Leave a Comment