[erlang-questions] wildcarded resource counters in Gproc

Ulf Wiger <>
Thu Dec 1 18:11:21 CET 2016

There's a new PR on Gproc, adding support for limited wildcard matching in
resource counters.


I don't know how many people use resource counters ('rc'), but thought I'd

The operation of registering (or unregistering) a resource now makes one
extra update_counter() protected by a try ... catch. My assumption is that
this extra overhead will be insignificant to just about all use cases, but
... does anyone out there want to disagree?

Briefly, when registering a resource ('r') object, gproc would try to
perform an update_counter on the corresponding 'rc' object - an operation
that might fail if the 'rc' object doesn't exist. Now, if the name of the
resource is a tuple, it also tries to update an 'rc' object with the last
element of the name tuple replaced with '\\_'. This make it possible to
count resources whose names differ in only the last tuple element. For
non-tuple resource names, it works just like before.

Ulf W
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