shri314 / timer

timer

This is a C++ header only timer library - that allows scheduling of functions to be excecuted after a specified duration in time has elapsed. The bundled tests can be built and run.

Prequisites for using library

• A C++17 compliant compiler.
  • Tested with g++ 9.4.0 (Ubuntu20.04)
  • Tested with clang++ 14.0.0 (Ubuntu22.04)

Prequisites for building Tests

• cmake (a fairly recent version >= 3.12 will work)
• make

Warning: On g++11 on Ubuntu22.04 has some problems in the thread sanitizer module running into false positives. See https://gcc.gnu.org/bugzilla//show_bug.cgi?id=101978

Building Tests

#Get the source
git clone https://github.com/shri314/timer.git

cd timer
( mkdir -p out && cd out && cmake .. )
make -C out VERBOSE=1 -j4

the above will build release, debug, and sanitizer versions of the test binaries

Running Tests

./a.out.release
./a.out.tsan

Library Documentation

Creating the timer:

#include <shri314/timer/Timer.hpp>

shri314::timer::Timer t;

One one needs to call t.run() on a separate thread. This function blocks until someone stops the timer using a t.request_stop().

Scheduling a one-shot function:

auto token = t.schedule( 5s, []() { std::cout << "hello timer\n"; } );
                         ^^

This will cause the function provided to be executed after 5sec, as long as:

• t.run() is stil running
• token is kept alive and is in scope (not destroyed)
• token.cancel() has not been called.
• token.request_stop() has not been called.
• the callback has not been already executed.

The token object helps keep the registration alive. when token goes out of scope, it automatically issues a cancel(). Before the callback, the token object can be used to cancel the registration. After the callback the token object when queried will indicate that it has expired.

Scheduling a repeating function:

auto token = t.schedule( 5s, []() { std::cout << "hello timer\n"; }, 10s );
                                                                     ^^^

The behavior is like the previous example, except, that at after the first call subsequently, the same function will be called every 10s. Unlike the one shot case, the token object will continue to indicate that is has not expired.