The Same C++ Struct Is 24 Bytes on Linux and 12 on Windows

📰 Medium · Programming

Understand how C++ struct size varies between Linux and Windows due to padding, alignment, and LP64 vs LLP64 differences

intermediate Published 31 Aug 2026
Action Steps
  1. Check the size of a C++ struct on Linux using sizeof()
  2. Compare the size of the same struct on Windows
  3. Investigate the role of padding and alignment in struct size differences
  4. Research the implications of LP64 vs LLP64 on struct size and memory layout
  5. Use compiler flags or directives to control struct packing and alignment
Who Needs to Know This

Software engineers and developers working with C++ on multiple platforms will benefit from understanding these differences to optimize their code

Key Insight

💡 Struct size differences between Linux and Windows are due to padding, alignment, and LP64 vs LLP64 differences

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🤔 Did you know the same C++ struct can have different sizes on Linux and Windows? 📊

Full Article

Your fields add up to 11. The other 13 bytes are padding, alignment, and the LP64 vs LLP64 split. Continue reading on Medium »
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