+ return 127.
+ Arguments:
+ - child is the pid of the subprocess.
+ - progname is the name of the program executed by the subprocess, used for
+ error messages.
+ - If ignore_sigpipe is true, consider a subprocess termination due to
+ SIGPIPE as equivalent to a success. This is suitable for processes whose
+ only purpose is to write to standard output. This flag can be safely set
+ to false when the process' standard output is known to go to DEV_NULL.
+ - If null_stderr is true, the usual error message to stderr will be omitted.
+ This is suitable when the subprocess does not fulfill an important task.
+ - slave_process should be set to true if the process has been launched as a
+ slave process.
+ - If exit_on_error is true, any error will cause the main process to exit
+ with an error status.
+ - If termsigp is not NULL: *termsig will be set to the signal that
+ terminated the subprocess (if supported by the platform: not on native
+ Windows platforms), otherwise 0, and the error message about the signal
+ that terminated the subprocess will be omitted.
+ Prerequisites: The signal handler for SIGCHLD should not be set to SIG_IGN,
+ otherwise this function will not work. */