| alarm | Causes a signal to be sent to the calling process after a specified timeout. | 
| kill or killpg | Sends a signal to a process or a group of processes. | 
| pthread_atfork | Registers fork cleanup handlers. | 
| pthread_kill | Sends a signal to the specified thread. | 
| raise | Sends a signal to the executing program. | 
| sigaction, sigvec, or signal | Specifies the action to take upon delivery of a signal. | 
| sigsuspend or sigpause | Atomically changes the set of blocked signals and waits for a signal. | 
| sigthreadmask | Sets the signal mask of a thread. | 
| sigwait | Blocks the calling thread until a specified signal is received. | 
Threads-Processes Interactions Overview.
Threads Library Quick Reference.