Tom Brinkman wrote:

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Rather than an implementation, could you provide an example of a documentation, stating precisely what the return value should be?

Basically, I just want to return the numeric value that is returned by sprintf.

Example:

char ch[255]; sprintf(ch, "%.2f", 333.444);

boost::numeric_cast<double>(ch) == boost::round(333.444,2) == 33.44;

Right, but you can never round exactly to a decimal: for example if you round 0.1 to one decimal place the result won't be exactly 0.1 (any more than it was exactly that value to begin with). John.