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Automate initialization of raw structure

By Mark W. Kaelin Editor ·
The Jan. 15, C++ TechMail discusses the use of raw_initialize to automate initialization of raw structures. Have you been required to initialize a raw structure in your application development? How did you accomplish the task?

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Assumes contiguous memory, no float bias

by tehilinski In reply to Automate initialization o ...

My understanding of the C and C++ standards is that member variables of a structure are not guaranteed to be contiguously allocated. For example:
struct RawData {
float x;
int n;
};
Here, if x and n are not contiguous, then memset will overwrite memory not allocated to the variables.
Also, on some hardware architectures, floats == 0.0 do not have zero in their machine representation, due to a bias value. In this case, filling an array of floats with NULL may not be the same (depending upon the implementation of memset) as assigning zero to the individual variables.

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Yes, but...

by John Torjo In reply to Assumes contiguous memory ...

You are true: variables are not guaranteed to be contigously allocated. But in this case, you don't care about the "memory between" (the memory that is not used) - it can be initialized with zeros.

However, you're right about the float. Same applies to double/ long double. In such a (rare) case, you will need a different technique.

Thanks.

Best,
John

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A simpler way

by achalk In reply to Automate initialization o ...

Why not just:

struct fred f = {0};

Regards

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