Function: format_paragraph File: options_description.cpp, line 423: if (last_space != line_begin) { // is last_space within the second half ot the // current line if ((unsigned)distance(last_space, line_end) < (line_length - indent) / 2) // "- indent" ? { line_end = last_space; } } I'm given to understand that the code around here is designed to split the description at a space, iff the space occurs at least half-way through the description text. The code currently subtracts the indent from the line_length, where the line_length (within format_paragraph) represents the space available for the description (indent has already been subtracted from line_length at the beginning of format_paragraph). The result is that the longer the option names, the less chance of the split occurring at a space within the description. Was this the intention? E.g. if an option is 40 chars long, then there is no chance of it splitting at a space (for 80 column default).