Hi,
I am reasonably new to Boost.Asio. Below is a short test program to
catch CNTR C. It nearly works as i would have expected.
#include <iostream>
#include
#define BOOST_ASIO_ENABLE_HANDLER_TRACKING
#include
namespace asio = boost::asio;
#define GCC_VERSION (__GNUC__*10000 + __GNUC_MINOR__*100 +
__GNUC_PATCHLEVEL__ )
struct Sig_handler {
Sig_handler(int& count, asio::signal_set& signals) : count_(count),
signals_(signals) {}
void operator()(const boost::system::error_code& ec, int signal_number) {
if (!ec) {
count_++;
std::cout << "signal: " << signal_number << std::endl;
if (count_ < 3)
signals_.async_wait( Sig_handler(count_, signals_));
}
else {
std::cout << "Sig_handler error" << std::endl;
}
}
int& count_;
asio::signal_set& signals_;
};
int main()
{
std::cout << "test_asio_sig starting " << std::endl;
std::cout << "GCC VERSION " << GCC_VERSION << std::endl;
std::cout << "BOOST VERSION " << BOOST_VERSION << std::endl;
asio::io_service io_service;
asio::signal_set signals(io_service, SIGINT);
int count = 0;
std::cout << "count " << count << std::endl;
signals.async_wait( Sig_handler(count, signals) );
size_t num_handlers = io_service.run();
// size_t num_handlers = io_service.run_one(); // <<== NOTE
std::cout << "num handlers " << num_handlers << std::endl;
std::cout << "count " << count << std::endl;
std::cout << "test_asio_sig finishing " << std::endl;
}
Here is the output after pressing CNTR C 3 times
[robert@localhost misc]$ ./test_asio_sig
test_asio_sig starting
GCC VERSION 40902
BOOST VERSION 105700
count 0
@asio|1425176527.462503|0*1|signal_set@0x7fffcd9139b8.async_wait
^C@asio|1425176530.453067|>1|ec=system:0,signal_number=2
signal: 2
@asio|1425176530.453092|1*2|signal_set@0x7fffcd9139b8.async_wait
@asio|1425176530.453102|<1|
^C@asio|1425176533.749159|>2|ec=system:0,signal_number=2
signal: 2
@asio|1425176533.749187|2*3|signal_set@0x7fffcd9139b8.async_wait
@asio|1425176533.749191|<2|
^C@asio|1425176548.261061|>3|ec=system:0,signal_number=2
signal: 2
@asio|1425176548.261092|<3|
num handlers 6
count 3
test_asio_sig finishing
@asio|1425176548.261116|0|signal_set@0x7fffcd9139b8.cancel
[robert@localhost misc]$
I don't understand why io_service.run() says 6 handlers where invoked
but otherwise it seems OK.
Now if i replace io_service.run() with io_service.run_one() i
expected the handler to be invoked once when CNTR C is pressed. Here
is the output
[robert@localhost misc]$ ./test_asio_sig
test_asio_sig starting
GCC VERSION 40902
BOOST VERSION 105700
count 0
@asio|1425176928.548934|0*1|signal_set@0x7fffe64b8398.async_wait
^Cnum handlers 1
count 0
test_asio_sig finishing
@asio|1425176930.187377|0|signal_set@0x7fffe64b8398.cancel
@asio|1425176930.187411|~1|
[robert@localhost misc]$
This suggests one handler was invoked which is what i might have expected.
This does not have a line with >1 indicating entering the handler and
there is no output from the handler and count remains at 0.
Could someone help me to understand this.
[ I am using Fedora 21, gcc 4.9.2, x86_64, boost 1.57 ]
kind regards
