為什么在此函數中拋出此std :: out_of_range？

Question

下面是發生此錯誤的函數：

std::string DataTranslation::getMeshName(std::string meshLink)
{
    File input(this->datafilename);
    std::cout << "the line count of " << this->datafilename << " = " << input.lineCount() << ".\n";
    std::cout << "code above is working properly if this prints.\n";
    return "_";
}

運行：

the line count of ./res/data/resourcelist.data = 6.
code above is working properly if this prints.
terminate called after throwing an instance of 'std::out_of_range'
what(): vector::_M_range_check: __n (which is 0) >= this->size() (which is 0)

就是這樣。 以前，該功能要復雜得多，在調試過程中，我將其全部注釋掉了，剩下的就是我上面寫的內容。 由於return "_";似乎引發了異常return "_"; 。

我是在犯基本錯誤，還是真的很奇怪？

Answer 1

terminate called after throwing an instance of 'std::out_of_range'

terminate被調用通常是由於“逃避”析構函數的異常。

what(): vector::_M_range_check: __n (which is 0) >= this->size() (which is 0)

當您對std::vector的元素進行檢查訪問（認為.at() ）時，通常會拋出該異常。

因此，請在File析構函數內查找錯誤的選中矢量訪問。 更好的是，要調試此類問題，請在調試器中運行程序，甚至可以為拋出的異常添加一個斷點（或在std::terminate之上）； 請注意，使用gdb甚至不需SIGABRT std::terminate結果會生成SIGABRT ，它會自動進入調試器。

(gdb) r
Starting program: /home/matteo/scratch/a.out 
terminate called after throwing an instance of 'int'

Program received signal SIGABRT, Aborted.
0x00007ffff76c1418 in __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:54
54      ../sysdeps/unix/sysv/linux/raise.c: File o directory non esistente.
(gdb) bt
#0  0x00007ffff76c1418 in __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:54
#1  0x00007ffff76c301a in __GI_abort () at abort.c:89
#2  0x00007ffff7ae484d in __gnu_cxx::__verbose_terminate_handler() ()
   from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#3  0x00007ffff7ae26b6 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#4  0x00007ffff7ae2701 in std::terminate() () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#5  0x00007ffff7ae2919 in __cxa_throw () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#6  0x000000000040077e in A::~A() ()
#7  0x0000000000400729 in foo() ()
#8  0x0000000000400749 in main ()
(gdb)