CODEWITHSUNDEEP
cmemory-managementstructurepadding
Narasimha Reddy.P
Narasimha Reddy.P

Reputation: 163

How to avoid structure padding?

I'm curious to know about how #pragma will help to avoid stucture padding (please give me one programme to understand it).

By default compilers will allocate memory in an aligned manner. So by avoiding structure padding what will be the benifit programmer will get? When is it neccessary to avoid structure padding?

Upvotes: 1

Views: 8754

Answers (3)

anil
anil

Reputation: 11

structure paddding can be avoided by using a preprocessor directive #pragma 1 the compiler will alocate memory in multiples of one

Upvotes: 1

Rob
Rob

Reputation: 1974

The techniques depend on compiler.

The benefits are usually not much, other than potentially reducing the amount of memory consumed by your program. That benefit is only worth while on machines with few resources (e.g. memory) which means it is rarely needed with modern hardware.

In practice, the cost is reduced performance or hardware exceptions. The common purposes of padding are performance and avoiding hardware exceptions, by aligning struct members in a way that suits the host system. Disallowing padding basically turns off all the benefits of padding.

Saving a few bytes, or even a few kilobytes, is rarely worth the impact in terms of performance or more error conditions. If you are doing certain types of development (e.g. on embedded system with limited resources) it might be worthwhile, but even then not always.

Upvotes: 2

Vagish
Vagish

Reputation: 2547

1.Structure Padding is avoided mostly in case of resource critical embedded systems.In this case RAM is saved by packing the structure members on the expense of code memory(More Instructions are needed to access the packed structure member).

  1. In some cases an array of bytes is mapped to structure members for ease of accessing.

Upvotes: 1

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