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Conflicts with the x86 Compiler


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The latest version of this topic can be found at Conflicts with the x86 Compiler.

Data types that are larger than 4 bytes are not automatically aligned on the stack when you use the x86 compiler to compile an application. Because the architecture for the x86 compiler is a 4 byte aligned stack, anything larger than 4 bytes, for example, a 64-bit integer, cannot be automatically aligned to an 8-byte address.

Working with unaligned data has two implications.

  • It may take longer to access unaligned locations than it takes to access aligned locations.

  • Unaligned locations cannot be used in interlocked operations.

If you require more strict alignment, use __declspec(align(N)) on your variable declarations. This causes the compiler to dynamically align the stack to meet your specifications. However, dynamically adjusting the stack at run time may cause slower execution of your application.

Types and Storage