c++ - 「time.h」を使用するとクラッシュする

Question

==この行の下に最終クラス==

それは問題ではありませんでした。よく理解していないstd::ostringstream悪いことをしていました。"time.h"元の質問は、クラスの後に表示されます。最終的なクラスは次のようになります。

タイムスタンプ.h

#ifndef __TIMESTAMP_H
#define __TIMESTAMP_H

#include <string>
#include "time.h"


class CTimestamp {

    private:
        std::string timestamp;
        time_t rawtime;
        struct tm errorTime;
        struct tm tempTime;
        bool quality;

    public:
        CTimestamp();
        void set(std::string inputTime);
        std::string get();
        std::string get(int modifiedBy);
        bool good();

        void getWeekday();  // Mainly for testing purposes - if this returns
                            // the correct weekday for your modified timestamp,
                            // you probably modified it correctly.
};

#endif

タイムスタンプ.cpp

#include "timestamp.h"
#include "time.h"
#include <string>
#include <stdlib.h>
#include <iostream>
#include <sstream>

CTimestamp::CTimestamp(){

    quality = 0;
}

void CTimestamp::set(std::string inputTime){

    quality = 1;

    int year, month, day, hour, minute, second;

    if (19 == inputTime.length()){

        inputTime.replace(10,1," ");
        inputTime.replace(13,1,":");
        inputTime.replace(16,1,":");

        year = atoi(inputTime.substr(0,4).c_str());
        month = atoi(inputTime.substr(5,2).c_str());
        day = atoi(inputTime.substr(8,2).c_str());
        hour = atoi(inputTime.substr(11,2).c_str());
        minute = atoi(inputTime.substr(14,2).c_str());         
        second = atoi(inputTime.substr(17,2).c_str());

        timestamp = inputTime;
    }
    else{
        quality = 0;
    }

    if(quality){
        // Get current time with the "time_t time(struct tm * timeptr)" function from time.h
        time(&rawtime);

        // Change to local time with "struct tm * localtime (const time_t * timer)" function from time.h
        errorTime = *localtime(&rawtime);

        // Change to the time of the timestamp
        errorTime.tm_year = year - 1900;   //Years since 1900
        errorTime.tm_mon  = month - 1;     //Months since january
        errorTime.tm_mday = day;           //Day of the month
        errorTime.tm_hour = hour;      //Hours since midnight
        errorTime.tm_min  = minute;        //minutes since hour
        errorTime.tm_sec  = second;        //Seconds since minute

        // modifies errorTime so overflows in lower units increment higher units then sets tm_wday and tm_yday
        mktime ( &errorTime );
    }
}

void CTimestamp::getWeekday(){

    const char * weekday[] = {"sun", "mon", "tue", "wed", "thu", "fri", "sat"};
    std::cout << weekday[errorTime.tm_wday];
}

std::string CTimestamp::get(){
    std::string returnValue = "Bad Initialization";
    if(quality){
        returnValue = timestamp;
    }
    return returnValue;
}

std::string CTimestamp::get(int modifiedBy){

    std::string returnValue = "Bad Initialization";
    if(quality){

        tempTime = errorTime;
        tempTime.tm_sec = (errorTime.tm_sec+modifiedBy);
        mktime( &tempTime);

        std::string year, month, day, hour, minute, second;

        // This compiler does not support the C++11 std::to_string but there is a workaround with stringstreams
        // http://www.cplusplus.com/articles/D9j2Nwbp/
        year   = static_cast<std::ostringstream*>( &(std::ostringstream() << (tempTime.tm_year+1900)) )->str();
        month  = static_cast<std::ostringstream*>( &(std::ostringstream() << (tempTime.tm_mon+1)) )->str();
        day    = static_cast<std::ostringstream*>( &(std::ostringstream() << (tempTime.tm_mday)) )->str();
        hour   = static_cast<std::ostringstream*>( &(std::ostringstream() << (tempTime.tm_hour)) )->str();
        minute = static_cast<std::ostringstream*>( &(std::ostringstream() << (tempTime.tm_min)) )->str();
        second = static_cast<std::ostringstream*>( &(std::ostringstream() << (tempTime.tm_sec)) )->str();

        if(month.length()  == 1) { month  = "0" + month;  }
        if(day.length()    == 1) { day    = "0" + day;    }
        if(hour.length()   == 1) { hour   = "0" + hour;   }
        if(minute.length() == 1) { minute = "0" + minute; }
        if(second.length() == 1) { second = "0" + second; }

        returnValue = year+"-"+month+"-"+day+" "+hour+":"+minute+":"+second;
    }

    return returnValue;
}

bool CTimestamp::good(){

    return quality;
}

==元の質問はこの行の下から始まります==

カスタムのタイムスタンプ機能が必要で、そのためのクラスを作成しようとしています。残念ながら、関数の 1 つを呼び出そうとするとプログラムがクラッシュします。特に、小さなおもちゃのプログラムでクラスをテストするときにクラッシュしないという事実を考えると、その理由はよくわかりません。

#ifndef __TIMESTAMP_H
#define __TIMESTAMP_H

#include <string>
#include "time.h"
#include "debug.h"

class CTimestamp {

    private:
        std::string timestamp;
        time_t rawtime;
        struct tm * errorTime;
        struct tm * tempTime;
        bool quality;

    public:
        CTimestamp();
        void set(std::string inputTime);
        std::string get();
        std::string get(int modifiedBy);
        bool good();

        void getWeekday();  // Mainly for testing purposes - if this returns
                            // the correct weekday for your modified timestamp,
                            // you probably modified it correctly.
};

#endif

電話すると問題が発生します

std::cout << timeStamp.get(-30);

具体的には、この時点で:

year   = static_cast<std::ostringstream*>( &(std::ostringstream() << (tempTime->tm_year+1900)) )->str();

次のメソッドの一部です。

std::string CTimestamp::get(int modifiedBy){
    if ( 1 < __DEBUG__ ){std::cout << "\nDEBUG " << __FILE__ << " " << __FUNCTION__ << " " << __LINE__ ;}

    std::string returnValue = "Bad Initialization";
    if(quality){

        tempTime->tm_year  = errorTime->tm_year;
        tempTime->tm_mon   = errorTime->tm_mon;
        tempTime->tm_mday  = errorTime->tm_mday;
        tempTime->tm_hour  = errorTime->tm_hour;
        tempTime->tm_min   = errorTime->tm_min;
        tempTime->tm_sec   = errorTime->tm_sec;
        mktime(tempTime);

        tempTime->tm_sec = tempTime->tm_sec + modifiedBy;
        mktime(tempTime);

        std::string year, month, day, hour, minute, second;

        if ( 1 < __DEBUG__ ){std::cout << "\nDEBUG " << __FILE__ << " " << __FUNCTION__ << " " << __LINE__ ;}

        // This compiler does not support the C++11 std::to_string but there is a workaround with stringstreams
        // http://www.cplusplus.com/articles/D9j2Nwbp/
        year   = static_cast<std::ostringstream*>( &(std::ostringstream() << (tempTime->tm_year+1900)) )->str();
        month  = static_cast<std::ostringstream*>( &(std::ostringstream() << (tempTime->tm_mon+1)) )->str();
        day    = static_cast<std::ostringstream*>( &(std::ostringstream() << (tempTime->tm_mday)) )->str();
        hour   = static_cast<std::ostringstream*>( &(std::ostringstream() << (tempTime->tm_hour)) )->str();
        minute = static_cast<std::ostringstream*>( &(std::ostringstream() << (tempTime->tm_min)) )->str();
        second = static_cast<std::ostringstream*>( &(std::ostringstream() << (tempTime->tm_sec)) )->str();

        if ( 1 < __DEBUG__ ){std::cout << "\nDEBUG " << __FILE__ << " " << __FUNCTION__ << " " << __LINE__ ;}

        if(month.length() == 1)
        {
            month = "0" + month;
        }
        if(day.length() == 1)
        {
            day = "0" + day;
        }
        if(hour.length() == 1)
        {
            hour = "0" + hour;
        }
        if(minute.length() == 1)
        {
            minute = "0" + minute;
        }
        if(second.length() == 1)
        {
            second = "0" + second;
        }

        if ( 1 < __DEBUG__ ){std::cout << "\nDEBUG " << __FILE__ << " " << __FUNCTION__ << " " << __LINE__ ;}

        returnValue = year+"-"+month+"-"+day+" "+hour+":"+minute+":"+second;

        if ( 1 < __DEBUG__ ){std::cout << "\nDEBUG " << __FILE__ << " " << __FUNCTION__ << " " << __LINE__ ;}

    }

    if ( 1 < __DEBUG__ ){std::cout << "\nDEBUG " << __FILE__ << " " << __FUNCTION__ << " " << __LINE__ ;}

    return returnValue;
}

編集

これは私を奇妙にします：

電話すると

std::cout << timeStamp.get();

私が示した行でクラッシュします。

私が代わりに行くとき

std::string hey = timeStamp.get();
std::cout << hey;

2番目のステートメントでクラッシュします__DEBUG__（直後if(quality)）

編集 編集

errorTime はここで初期化されます:

void CTimestamp::set(std::string inputTime){

    quality = 1;

    int year, month, day, hour, minute, second;

    if (19 == inputTime.length()){

        inputTime.replace(10,1," ");
        inputTime.replace(13,1,":");
        inputTime.replace(16,1,":");

        year = atoi(inputTime.substr(0,4).c_str());
        month = atoi(inputTime.substr(5,2).c_str());
        day = atoi(inputTime.substr(8,2).c_str());
        hour = atoi(inputTime.substr(11,2).c_str());
        minute = atoi(inputTime.substr(14,2).c_str());         
        second = atoi(inputTime.substr(17,2).c_str());

        timestamp = inputTime;
    }
    else{
        quality = 0;
    }

    if(quality){
        // Get current time with the "time_t time(struct tm * timeptr)" function from time.h
        time(&rawtime);

        // Change to local time
        errorTime = localtime(&rawtime);

        // Change to the time of the timestamp
        errorTime->tm_year = year - 1900;   //Years since 1900
        errorTime->tm_mon  = month - 1;     //Months since january
        errorTime->tm_mday = day;           //Day of the month
        errorTime->tm_hour = hour;          //Hours since midnight
        errorTime->tm_min  = minute;        //minutes since hour
        errorTime->tm_sec  = second;        //Seconds since minute

        // modifies errorTime so overflows in lower units increment higher units then sets tm_wday and tm_yday
        mktime ( errorTime );
    }
}

編集 編集 編集

私は派手なポインターの作業を取り除き、これがさらに数行を占めるようにしました。残念ながら、うまくいかなかったようです:

    /*
    year   = static_cast<std::ostringstream*>( &(std::ostringstream() << (tempTime->tm_year+1900)) )->str();
    month  = static_cast<std::ostringstream*>( &(std::ostringstream() << (tempTime->tm_mon+1)) )->str();
    day    = static_cast<std::ostringstream*>( &(std::ostringstream() << (tempTime->tm_mday)) )->str();
    hour   = static_cast<std::ostringstream*>( &(std::ostringstream() << (tempTime->tm_hour)) )->str();
    minute = static_cast<std::ostringstream*>( &(std::ostringstream() << (tempTime->tm_min)) )->str();
    second = static_cast<std::ostringstream*>( &(std::ostringstream() << (tempTime->tm_sec)) )->str();
    */

    int timeConvertINT;
    std::ostringstream timeConvertOSS;

    timeConvertINT = (tempTime->tm_year)+1900;
    timeConvertOSS << timeConvertINT;
    year = timeConvertOSS.str();

    timeConvertINT = (tempTime->tm_mon)+1;
    timeConvertOSS << timeConvertINT;
    month = timeConvertOSS.str();

    timeConvertINT = (tempTime->tm_mday);
    timeConvertOSS << timeConvertINT;
    day = timeConvertOSS.str();

    timeConvertINT = (tempTime->tm_hour);
    timeConvertOSS << timeConvertINT;
    hour = timeConvertOSS.str();

    timeConvertINT = (tempTime->tm_min);
    timeConvertOSS << timeConvertINT;
    minute = timeConvertOSS.str();

    timeConvertINT = (tempTime->tm_sec);
    timeConvertOSS << timeConvertINT;
    second = timeConvertOSS.str();

編集 編集 編集 編集

は。そのため、ostreamstring はここでは違反者ではないようです。すべての OSS 機能をコメントアウトして、応答をハードコードしただけでも、その正確な行でクラッシュします。

これは、このブロックで次のことを意味します。

if(quality){

    if ( 1 < __DEBUG__ ){std::cout << "\nDEBUG " << __FILE__ << " " << __FUNCTION__ << " " << __LINE__ ;}

    tempTime->tm_year  = errorTime->tm_year;
    tempTime->tm_mon   = errorTime->tm_mon;
    tempTime->tm_mday  = errorTime->tm_mday;
    tempTime->tm_hour  = errorTime->tm_hour;
    tempTime->tm_min   = errorTime->tm_min;
    tempTime->tm_sec   = errorTime->tm_sec;
    mktime(tempTime);

    if ( 1 < __DEBUG__ ){std::cout << "\nDEBUG " << __FILE__ << " " << __FUNCTION__ << " " << __LINE__ ;}

    tempTime->tm_sec = tempTime->tm_sec + modifiedBy;
    mktime(tempTime);

    std::string year, month, day, hour, minute, second;

    if ( 1 < __DEBUG__ ){std::cout << "\nDEBUG " << __FILE__ << " " << __FUNCTION__ << " " << __LINE__ ;}

    year = "2013";
    month = "11";
    day = "05";
    hour = "12";
    minute = "00";
    second = "00";

次のように呼び出すと、最初のデバッグ出力が表示されます (その後は表示されません)。

std::string hey = timeStamp.get();
std::cout << hey;

しかし、私がそれを

std::cout << timeStamp.get();

直後にデバッグ出力が表示されます

std::string year, month, day, hour, minute, second;

Answer 1

不可解なクラッシュとポインタが一緒に発生するため、それらを逆参照する前に、それを確認して有効なオブジェクトtempTimeを指してください。errorTime投稿されたコードには、初期化する場所が表示されないtempTimeため、そこから探し始めます。

ポインターに値を割り当てることに加えて、ポインターを使用するときにオブジェクトの有効期間も有効であることを確認してください。スコープ外になった一時オブジェクトへのポインタを保存したくありません。