Templates - What potential problems are associated with their usage?

c0l0jar0 said:

If a template class requires a template argument to determine the size of a member array, will that mean the methods are "duplicated" each time a different template parameter is used to instantiate the class? Worried about code bloat.

Most of this code bloat can be avoided by compiling with optimization.

c0l0jar0 said:

Are all template functions inlined or are they the same as functions using the inline keyword where the compiler can decide when to inline them?

Strictly speaking, inlining of template functions is no different than other functions.  However, template functions are often very small, and thus are more likely to be inlined.  By building with --opt_level=2 or higher, the compiler automatically inlines most small functions.

When you say DSP, I presume you mean a C6000 DSP.  To get the full performance entitlement of C6000, you must allow the compiler to perform an optimization on your loops called software pipelining.  This software pipelining optimization is only performed if you build with --opt_level=2 or higher.  Thus, I presume you build with at least --opt_level=2, and thus most of your concerns about code bloat and inlining get addressed.

Thanks and regards,

-George

So since I am attempting to reduce code bloat I am trying to determine if using a template class with two different template parameters will cause duplication in memory of the function. For instance, I believe if the method uses the template argument heavily then the code will be compiled more than once and memory will be required for each "version" of that function. On the other hand, if the argument is not used in the function but the method is part of a template class will it duplicate the function each time a different template arg is used?

The second question was really asking the following. I have heard that all template functions are inline. Can the compiler choose to not inline these functions but instead even have a symbol in the MAP file for these functions if it chooses? Maybe when the function is very long?

What can I do to avoid bloating the code with template usage. We do use optimization levels higher than 2. The compiler does inline many functions that did not use that keyword. My question is, what does the compiler do to avoid inlining or what should i do to prevent problems.

Thanks

Chris