1. The Threading Demo
What is here
Copyright © 2017 Curt Hill

2. Introduction This presentation is on the Dev Threading demo
It puts the things to notice in one place
As such it introduces nothing new or testable
This demonstrates CreateThread, CreateProcess, Sleep and critical sections
Copyright © 2017 Curt Hill

3. Overview The demo is the standard ggFrm with the normal files
There are four additional:
Buffer.cpp and .h
Stuff.cpp and .h
The buffer is a concurrent producer and consumer problem
Stuff is to demonstrate the presence or absence of race errors
Copyright © 2017 Curt Hill

4. Threading and Synchronization
There is a #define that determines whether to use critical sections
It is in buffer.h and named CRITICAL
Commenting it out should provoke race errors
Copyright © 2017 Curt Hill

5. First Button The WxButton1Click0 event handler is where we start
It does the CreateThread in a loop limited by user defined input
It creates all of these suspended
It then starts them all at as close to one time as is practicable
The thread function is func
Defined in Stuff.cpp and .h
This is defined only to demonstrate race errors
Copyright © 2017 Curt Hill

6. Thread func This function must be a WINAPI function
It drops into a big for loop
It then increments and tests two integers
It then does a sleep for a millisecond
If the critical section is enabled there should be no race errors to find
Copyright © 2017 Curt Hill

7. Stuff Contains several integers and critical sections
Stuff is to increment these in succession, so that they are always within one of each other, but usually equal
The constructor initializes the critical section
Copyright © 2017 Curt Hill

8. Producer / Consumer
The second button starts a producer and consumer problem with multiple threads
Buffer contains the class and thread function
Copyright © 2017 Curt Hill

9. Starting a process
The last button does a common dialog box to start a new program
Its event handler does a CreateProcess
Copyright © 2017 Curt Hill

10. Finally
Let’s now look at the demo
Copyright © 2017 Curt Hill