Description Usage Arguments Format Details Value See Also
These functions give access to the state of the child process and to its exit status (return code).
timeout parameter can take one of three values:
0 which means no timeout
-1 which means "wait until there is data to read"
a positive integer, which is the actual timeout in milliseconds
TIMEOUT_INFINITE denotes an "infinite" timeout
(that is, wait until response is available) when waiting for an
operation to complete.
TIMEOUT_IMMEDIATE denotes an "immediate" timeout
(in other words, no timeout) when waiting for an operation to
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process_wait(handle, timeout = TIMEOUT_INFINITE) process_state(handle) process_return_code(handle) TIMEOUT_INFINITE TIMEOUT_IMMEDIATE
Process handle obtained from
Optional timeout in milliseconds.
An object of class
integer of length 1.
process_wait() checks the state of the child process
by invoking the system call
process_state() refreshes the handle by calling
process_wait() with no timeout and returns one of these
process_return_code() gives access to the value
returned also by
process_wait(). It does not invoke
process_wait() behind the scenes.
process_wait() returns an
integer exit code
of the child process or
NA if the child process has not exited
yet. The same value can be accessed by
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