Re: [PATCH 3/4] start_command: detect execvp failures early

Johannes Sixt [off-list ref] writes:

Previously, failures during execvp could be detected only by
finish_command. However, in some situations it is beneficial for the
parent process to know earlier that the child process will not run.

The idea to use a pipe to signal failures to the parent process and
the test case were lifted from patches by Ilari Liusvaara.

I wonder if we can do this without pipe, perhaps using "vfork, exec, then
update a variable"....