In Visual Studio I use #pragma pack(1) before struct which needs to be packed, and #pragma pack() after it to restore original setting.

How to make platform-independent way to turn off members and structures alignment in some piece of code?

In Visual Studio I use #pragma pack(1) before struct which needs to be packed, and #pragma pack() after it to restore original setting.

this depends on which compiler you plan to port your code for. with the gcc compiler you might specifiy alignment with the __attribute__ keyword:

struct foo
{
    int x[2] __attribute__ ((aligned(8)));
};

see: linkage

to make code portable with msvc i see no other option than using the preprocessor directives:

#ifdef WIN32

#else

#endif

but i might miss other possibilities