I've been trying to get a handle on cost of using Boost.format by looking at the interface, reading the docs, and, until my head exploded, looking at the source code. What I'd really like to know is whether simple output without reordering incurs the cost of an allocation (for a string or maybe a stringstream) for each argument. For example, should I, as a user, expect the following to potentially cost me three dynamic memory allocations? cout << format("%1% %2% %3%") % 86 % 100.55 % "Hello"; The doc says this:

Since common stream implementations eventually call functions of the printf family for the actual formatting of numbers, in general printf will be noticeably faster than the direct stream operations And due to to the reordering overhead (allocations to store the pieces of string, stream initialisation at each item formatting, ..) the direct stream operations would be faster than boost::format, (one cas expect a ratio ranging from 2 to 5 or more)

This suggests that per-argument buffering to support reordering may cost an allocation per argument, but if there is no reordering, does one pay this cost? I could figure this out on my own given enough time, but I'm hoping that others familiar with this library already know the answer and can save me the trouble. Thanks, Scott