Previous: Accepting Output, Up: Output from Processes
Because threads were a relatively late addition to Emacs Lisp, and
due to the way dynamic binding was sometimes used in conjunction with
accept-process-output, by default a process is locked to the
thread that created it. When a process is locked to a thread, output
from the process can only be accepted by that thread.
A Lisp program can specify to which thread a process is to be
locked, or instruct Emacs to unlock a process, in which case its
output can be processed by any thread. Only a single thread will wait
for output from a given process at one time—once one thread begins
waiting for output, the process is temporarily locked until
accept-process-output or sit-for returns.
If the thread exits, all the processes locked to it are unlocked.