OpenThreads is a C++ based threading library. Its largest userbase seems to OpenSceneGraph so you might notice I accept OSGDIR as an environment path. I consider this part of the Findosg* suite used to find OpenSceneGraph components. Each component is separate and you must opt in to each module.
Locate OpenThreads This module defines OPENTHREADS_LIBRARY OPENTHREADS_FOUND, if false, do not try to link to OpenThreads OPENTHREADS_INCLUDE_DIR, where to find the headers
$OPENTHREADS_DIR is an environment variable that would correspond to the ./configure –prefix=$OPENTHREADS_DIR used in building osg.
[CMake 2.8.10]: The CMake variables OPENTHREADS_DIR or OSG_DIR can now be used as well to influence detection, instead of needing to specify an environment variable.
Created by Eric Wing.
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Licensed under the BSD 3-clause License.
https://cmake.org/cmake/help/v3.19/module/FindOpenThreads.html