【发布时间】：2014-03-23 13:03:26
【问题描述】：
好吧，我一直在尝试我所知道的一切来让这个程序停止崩溃，但我就是不明白为什么。我能够使用 ctime 将问题隔离到代码中，并且只是制作了一个小程序来演示出了什么问题。这段代码编译没有问题。
#include<iostream>
#include<ctime>
int main();
time_t getDay(time_t t);
int diffDay(time_t end,time_t begin);
int main()
{
time_t curTime=time(NULL); //Assign current time
time_t curDay=getDay(curTime); //Assign beginning of day
time_t yesterday=curDay-16*60*60; //Assign a time that's within yesterday
time_t dif=diffDay(curTime,yesterday); //Assign how many days are between yesterday and curTime
std::cout << "Cur Time: " << curTime << '\n'
<< "Cur Day: " << curDay << '\n'
<< "Yes Day: " << dif << '\n' << std::flush;
char a;
std::cin >> a; ///Program crashes after here.
return 0;
}
///Get beginning of day that t is a part of
time_t getDay(time_t t)
{
//Get current time
struct tm* loctim=localtime(&t);
if(loctim==0)
return 0;
//Set loctim to beginning of day
loctim->tm_sec=0;
loctim->tm_min=0;
loctim->tm_hour=0;
//Create a int from the new time
int reval=mktime(loctim);
//Free memory
delete loctim;
return reval;
}
///Calculate how many days are between begin and end
int diffDay(time_t end,time_t begin)
{
time_t eDay=getDay(end); //Get beginning of day end is a part of
time_t bDay=getDay(begin); //Get beginning of day begin is a part of
time_t dif=(eDay-bDay)/(24*60*60); //Get how many days (86400 seconds)
return dif;
}
这是我从调试中得到的一些文本。
调用堆栈
#0 77BC3242 ntdll!LdrLoadAlternateResourceModuleEx() (C:\Windows\system32\ntdll.dll:??)
#1 00000000 0x6d067ad3 in ??() (??:??)
#2 00000000 0x00000018 in ??() (??:??)
#3 77BC3080 ntdll!LdrLoadAlternateResourceModuleEx() (C:\Windows\system32\ntdll.dll:??)
#4 00000000 0x00000018 in ??() (??:??)
#5 77C60FCB ntdll!TpCheckTerminateWorker() (C:\Windows\system32\ntdll.dll:??)
#6 00000000 0x007f0000 in ??() (??:??)
#7 00000000 0x50000163 in ??() (??:??)
#8 00000000 0x00000018 in ??() (??:??)
#9 77C1AC4B ntdll!RtlReAllocateHeap() (C:\Windows\system32\ntdll.dll:??)
#10 00000000 0x007f0000 in ??() (??:??)
#11 00000000 0x50000163 in ??() (??:??)
#12 00000000 0x00000018 in ??() (??:??)
#13 77BC3080 ntdll!LdrLoadAlternateResourceModuleEx() (C:\Windows\system32\ntdll.dll:??)
#14 00000000 0x00000018 in ??() (??:??)
#15 769A9D45 msvcrt!malloc() (C:\Windows\syswow64\msvcrt.dll:??)
#16 769AF5D3 strcpy_s() (C:\Windows\syswow64\msvcrt.dll:??)
#17 769B2B18 open_osfhandle() (C:\Windows\syswow64\msvcrt.dll:??)
#18 00000000 0x00000018 in ??() (??:??)
#19 769B3C7D msvcrt!_get_fmode() (C:\Windows\syswow64\msvcrt.dll:??)
#20 769BA6A0 msvcrt!_fsopen() (C:\Windows\syswow64\msvcrt.dll:??)
#21 00000000 0xc3458a06 in ??() (??:??)
#22 00000000 0x00000000 in ??() (??:??)
这里还有来自同一构建的另一个调用堆栈。
#0 77BE708C ntdll!RtlTraceDatabaseLock() (C:\Windows\system32\ntdll.dll:??)
#1 00000000 0x6ccdaf66 in ??() (??:??)
#2 00000000 0x00000000 in ??() (??:??)
这是一些特殊的构建选项吗？我正在使用 -std=c++0x 但决定在没有它的情况下尝试该程序，但它仍然崩溃。感谢您的帮助，我整天都在努力解决这个问题。
【问题讨论】：
-
尝试使用 gdb 运行程序来定位问题所在。如果您对 gdb 不熟悉，您可以简单地在每行之后添加 cout 语句以在运行时跟踪程序。
标签： c++ segmentation-fault undefined-behavior localtime