Arguments:
- _wait_threads,"command1","command2",...
Description:
Execute specified commands in parallel, each in a different thread.
Parallel threads share the list of images.
wait_threads can be
{ 0=when current environment ends | 1=immediately }.
Default values:
wait_threads=1.
Example of use:
$ gmic
image.jpg [0] parallel "blur[0] 3","mirror[1] c"

Command:
image.jpg [0] parallel "blur[0] 3","mirror[1] c"

Command:
image.jpg [0] parallel "blur[0] 3","mirror[1] c"