document @printf,@sprintf, fixes #1170

[ihnorton]

No description provided.

[JeffBezanson]

There should also be changes in base.rst.

[diegozea]

Is @printf a wrapper for C's printf ? Is faster than using write ? If answers are yes, maybe can be added to the description.

[JeffBezanson]

No, we have our own implementation of printf (see base/printf.jl). It could eventually be faster than C's since we compile the format string.

[diegozea]

Thanks!! I need to check out more about file IO.

[pao]

@ihnorton More explanation of what Jeff said--helpdb.jl is a generated file (make -C doc helpdb.jl if you have Sphinx installed) based on the ReStructuredText files. #2501 should make this less confusing for documentation contributors since the file would no longer be in the tree. At any rate, any changes you make directly to helpdb.jl will be lost next time someone regenerates it and checks it in.

[ihnorton]

@pao thanks for the explanation, should have realized that. I installed Sphinx and updated both this time.

[pao]

Great, thanks!

[pao]

Might be nice to mention why you would use @printf/@sprintf instead of their functional equivalents.