process_read() reads data from one of the child process' streams,
standard output or standard error output, and returns
it as a
process_write() writes data into child's
standard input stream.
process_close_input() closes the write end
of the pipe whose read end is the standard input stream of the
child process. This is a standard way to gracefully request the child
process to exit.
PIPE_STDOUT: read from child's standard output.
PIPE_STDERR: read from child's standard error
PIPE_BOTH: read from both child's output streams:
standard output and standard error output.
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Process handle obtained from
Output stream identifier:
Optional timeout in milliseconds.
If there is any data within the given
Input for the child process.
process_read() then the invocation of
read() system-call will be repeated until
the pipe buffer is empty.
pipe is set to either
the returned value is a single list with a single key, stdout or
stderr, respectively. If
pipe is set to
list contains both keys. Values in the list are
character vectors of 0 or more elements, lines read from the
respective output stream of the child process.
For details on
process_read returns a
list containing either of
or both keys: stdout and stderr; the value is in
both cases a
character vector which contains lines of
process_write returns the number of characters