What does each thread get its own copy of?
Automatic variables (function variables)
What data do threads share?
- Open file handles and sockets
- Global variables
- Memory allocated with malloc
Give four reasons threads are useful
- Increased responsiveness
- Ease of communication between threads
- Scalability
- Handling asynchronous events
How do threads increase the responsiveness of a program?
There can be separate threads for IO while others do computation.
What library implements POSIX threads?
pthreads
What is the function used to create a new thread in C?
pthread_create()
What is the function prototype of pthread_create?
int pthread_create(
pthread_t *restrict thread,
const pthread_attr_t *restrict attr,
void *(*start_routine)(void*),
void *restrict arg);What are two ways for a thread to exit?
- It returns from its start routine
- It calls pthread_exit
What is the function prototype for pthread_exit?
void pthread_exit(void *value_ptr);
What happens to threads when a process terminates?
They also terminate.
What function is used to get the current thread’s ID?
pthread_self
What is the function prototype for pthread_self?
pthread_t pthread_self(void);
What makes a function thread-safe?
When the correct result is produced in the face of simultaneous execution.
What gcc parameter is used to link the pthread library?
-pthread
What function is used to wait for a thread to terminate?
pthread_join
What does the pthread_join function do?
Waits for a thread to terminate and receives its return value.
What is the function prototype for pthread_join?
int pthread_join(pthread_t thread, void **value_ptr);
What function is used to request termination of another thread?
pthread_cancel
What is the function prototype of pthread_cancel?
int pthread_cancel(pthread_t thread);
What does the pthread_cancel function do?
Requests the termination of another thread.
