basic_signal_set::add (4 of 4 overloads)

Add a signal to a signal_set with the specified flags.

void add(
    int signal_number,
    flags_t f,
    asio::error_code & ec);

This function adds the specified signal to the set. It has no effect if the signal is already in the set.

Flags other than flags::dont_care require OS support for the sigaction call, and this function will fail with error::operation_not_supported if this is unavailable.

The specified flags will conflict with a prior, active registration of the same signal, if either specified a flags value other than flags::dont_care. In this case, the add will fail with error::invalid_argument.

Parameters

signal_number: The signal to be added to the set.
f: Flags to modify the behaviour of the specified signal.
ec: Set to indicate what error occurred, if any.