c++ - 无法捕获异常

Question

这是完整的代码:TomTimers::set() 会抛出异常，但 tom_timing_test.cpp 中的 try/catch block 似乎没有捕获到它。当我运行它时，我得到这个:

terminate called after throwing an instance of 'TomTimers_Exception'
Aborted (core dumped)

tom_timing_test.h

#ifndef TOM_TIMING_TEST_H
#define  TOM_TIMING_TEST_H

#include <time.h>
#include <sys/time.h>
#include <utility>

typedef struct timespec timespec_t;

#define ORWL_NANO (+1.0E-9)
#define ORWL_GIGA UINT64_C(1000000000)

// =============================================================================
#ifdef __MACH__ // support for OS X
// =============================================================================

#include <mach/clock.h>
#include <mach/mach.h>
#include <mach/mach_time.h>

// timebase is a scaling factor that converts the difference between
// two mach_absolute_times into seconds.
static double   orwl_timebase = 0.0;
static uint64_t orwl_timestart = 0;

timespec_t porta_gettime(void) {
    if (!orwl_timebase) {
    mach_timebase_info_data_t tb;
    mach_timebase_info(&tb);
    orwl_timebase = tb.numer;
    orwl_timebase /= tb.denom;
    orwl_timestart = mach_absolute_time();
    }
    timespec_t t;
    double diff = (mach_absolute_time() - orwl_timestart) * orwl_timebase;
    t.tv_sec = diff * ORWL_NANO;
    t.tv_nsec = diff - (t.tv_sec * ORWL_GIGA);
    return t;
}

// =============================================================================
#else   // support for Linux
// =============================================================================

// porta_gettime() - Get real time as a timespec_t
// timespec{sec, nsec}
timespec_t porta_gettime(void) {
    timespec_t tnow;
    clock_gettime(CLOCK_REALTIME, &tnow);
    return tnow;
}

#endif
// =============================================================================


#include <string>
#include "wd_sprintf.h"
#include <iostream>
#include <set>
#include <boost/foreach.hpp>
#include <boost/unordered_map.hpp>

using std::set;
using std::cout;
using std::endl;
using std::string;
using boost::unordered_map;


typedef struct  {
    double avg_onset;
    double avg_duration;
    long   samples;
} Average;

typedef unordered_map<string, Average>      Average_Map;
typedef unordered_map<string, timespec_t>   Timer_Map;

static timespec_t  t0;       // absolute timebase
static const Average init_avg {0,0,0};

class TomTimers_Exception : std::runtime_error {
public:
    TomTimers_Exception(string const& msg) : std::runtime_error(msg) {}
};

class TomTimers {
public:
    TomTimers() {
    t0 = porta_gettime(); // set an absolute timebase
    }

    void set() {
        if ( !_timer_map.empty() ) {
            // There are still running timers.  Usage error.
            throw TomTimers_Exception("TomTimers::set() called with active timers.");
        }
        _cycle = porta_gettime(); // set the start-of-cycle time
    }

    void start(const string& id) {
    timespec_t now = porta_gettime(); // get real time
    start(id, now);
    }
    void start(const string& id, timespec_t time) {
    _timer_map[id] = time;
    _average_map.insert(std::make_pair(id, init_avg));
    }

    timespec_t stop(const string& id) {
        timespec_t ts_start = _timer_map[id];
        timespec_t ts_stop  = porta_gettime();
        Average    previous = _average_map[id];
        timespec_t tdur;

        // Compute this duration and update avg duration
        tdur.tv_sec  = ts_stop.tv_sec - ts_start.tv_sec; // can't be neg
        tdur.tv_nsec = ts_stop.tv_nsec - ts_start.tv_nsec; // might be neg
    double new_duration = tdur.tv_sec * ORWL_GIGA + tdur.tv_nsec;
    _average_map[id].avg_duration =
        (previous.avg_duration * previous.samples + new_duration)
        / (_average_map[id].samples + 1);

    // Compute this onset and update avg onset
        tdur.tv_sec  = ts_start.tv_sec - _cycle.tv_sec; // can't be neg
        tdur.tv_nsec = ts_start.tv_nsec - _cycle.tv_nsec; // might be neg
    double new_onset = tdur.tv_sec * ORWL_GIGA + tdur.tv_nsec;
    _average_map[id].avg_onset =
        (previous.avg_onset * previous.samples + new_onset)
        / (_average_map[id].samples + 1);

    ++(_average_map[id].samples);

        _timer_map.erase(id);
    return ts_stop;
    }

    // stop_start(id1, id2)
    //
    // Stops id1's timer and starts id2's timer at the same time.
    void stop_start(const string& id_stop, const string& id_start) {
        start(id_start, stop(id_stop));
    }

    void dump() {
    // Sort the names by copying them into an ordered set
    // and why the FUCK do I have to say std:: ???
    std::set<string> ordered_set;
    BOOST_FOREACH( Average_Map::value_type& i, _average_map) {
        ordered_set.insert(i.first);
    }

        BOOST_FOREACH(const std::set<string>::value_type& v, ordered_set) {
            cout << wd_sprintf("%s: Onset %12.8f Dur %12.8f [%d samples]",
                   v,
                   _average_map[v].avg_onset,
                   _average_map[v].avg_duration,
                   _average_map[v].samples)
         << endl;
        }
    }

private:

    timespec_t  _cycle;
    Timer_Map   _timer_map;
    Average_Map _average_map;

};


#endif

tom_timing_test.cpp

#include "tom_timing_test.h"

int
main( int argc, char** argv) {

    long repetitions;
    if (argc > 1) {
        repetitions = atoi(argv[1]);
    }
    else {
        cout << "You need repetitions" << endl;
        return 0;
    }

    TomTimers tt;

    const string DUR_1 {"Phase 1"};
    const string DUR_2 {"Phase 2"};
    const string DUR_3 {"Phase 3"};

    try {
        for (int i = 0; i < repetitions; ++i) {
            tt.set();
            tt.start(DUR_1);
            //        sleep(1);
            tt.stop_start(DUR_1, DUR_2);
            //        sleep(2);
            tt.stop_start(DUR_2, DUR_3);
            //        sleep(2);        
            //  tt.stop(DUR_3);
        }

        tt.dump();
    }
    catch (std::exception& e) {
        cout << "Caught exception: " << e.what() << endl;
    }
}

Answer 1

好吧，现在，当您捕获为 exception 时，抛出的类必须是 exception 或具有 exception 作为可访问(在本例中表示 public)基类。