Optimizing Member Alignment

A class’s size can change simply by playing with the order of its members’ declaration. For example:

 struct A{ bool a; int b; bool c;}; // sizeof (A) == 12

On my machine, sizeof (A) equals 12. This result might seem surprising because the total size of A’s members is only 6 bytes: 1+4+1 bytes. Where did the remaining six bytes come from? The compiler inserted three padding bytes after each bool member to make it align on a word boundary. You can reduce A’s size by reorganizing its data members as follows:

 struct B{ bool a; bool c; int b;}; // sizeof (B) == 8

This time, the compiler inserted only two padding bytes after the member c. Because b occupies four bytes, it naturally aligns on a word boundary without necessitating additional padding bytes.

As a rule, if your class has several data members of various types,declare the members that occupy a small size (less than the size of anint) successively.

Share the Post:
Share on facebook
Share on twitter
Share on linkedin

Overview

The Latest

Top 5 B2B SaaS Marketing Agencies for 2023

In recent years, the software-as-a-service (SaaS) sector has experienced exponential growth as more and more companies choose cloud-based solutions. Any SaaS company hoping to stay ahead of the curve in this quickly changing industry needs to invest in effective marketing. So selecting the best marketing agency can mean the difference

technology leadership

Why the World Needs More Technology Leadership

As a fact, technology has touched every single aspect of our lives. And there are some technology giants in today’s world which have been frequently opined to have a strong influence on recent overall technological influence. Moreover, those tech giants have popular technology leaders leading the companies toward achieving greatness.

iOS app development

The Future of iOS App Development: Trends to Watch

When it launched in 2008, the Apple App Store only had 500 apps available. By the first quarter of 2022, the store had about 2.18 million iOS-exclusive apps. Average monthly app releases for the platform reached 34,000 in the first half of 2022, indicating rapid growth in iOS app development.