C++ Footprint and Performance Optimization

Grouping Base Types

This section looks at ways to achieve optimizations in grouped C/C++ types. The way in which grouped types are created has an impact on the footprint as well as the performance of the type.

Structs

The use of structures as data containers seems pretty straightforward, which it is really, when you take one or two things into account before using structures for large sets of data. Listing 6.9 demonstrates several ways of creating a grouped type.

Code Listing 6.9. Structure Sizes

// Structure Size example #include <iostream.h> struct A { char a; long b; char c; long d; } ; struct B { char a; char c; long b; long d; } ; #pragma pack(push,1) struct C { char a; long b; char c; long d; } ; #pragma pack(pop) void main(void) { cout ...