function::ngroups.3stap man page

function::ngroups — Number of subexpressions in the last match.

Synopsis

    ngroups:long()

Arguments

None

Description

returns the number of subexpressions from the last successful use of the =~ regex matching operator.

Note that this number includes subexpressions which are present in the regex but did not match any string; for example, given the regex “a|(b)”, the subexpressions will count the group for (b) regardless of whether it matched a string or not. Throws an error if the last use of =~ was a failed match.

See Also0

tapset::regex(3stap)

Info

October 2017 SystemTap Tapset Reference A collection of standard strin