Pointers and small data types

Dizz · 03-01-2004 07:04PM #1

Howdee thar
apart from the obvious (by val, by ref) are there any advantages in passing a small data type, such as an ushort as a reference? Any increases in perf? Just a nuance of a Q....

Dizz

tendofan · 05-01-2004 04:16PM

AFAIK, and please correct me if I'm wrong, but if it's something like a simple int then it doesn't make any difference, apart from the obvious value/reference advantages.

However, if it's a structure, then there may be speed advantages depending on how it's padded internally by
the compiler.

Having said that, it's _usually_ more important to get
your design right than worry about micro-seconds shaved off something by passing by reference.

Tendofan.

Skyclad · 07-01-2004 12:40PM

For a 32 bit system, the pointer size should be 4 bytes, or the same size as an int. A short is 2 bytes, so by passing a pointer to a short, you are in effect passing slightly more data then the actual variable. OTOH, depending on the compiler, there are better speed optimisations for int values (which could apply to pointers too since they take up the same amount of memory). For any larger structures (classes, structs etc) you almost always want to pass them by reference, declaring them as const if you are not going to modify any of their values.

Dave

Dizz · 07-01-2004 06:09PM

For a 32 bit system, the pointer size should be 4 bytes

Just the answer I needed

Should of really asked the Q - what's the size of a pointer on win32 :rolleyes:

Cheers
Dizz

Pointers and small data types

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