本文介绍了SIGSEGV在std :: sort中，如何缩小它的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
这是与相关的文章，因为它处理相同的程序，但我现在实现它的迭代，不再递归，但我仍然得到SIGSEGV（但后来），而运行程序。我对我的程序做了一些其他修改，以缩小它，我想，更改一个对象的向量到ptr的对象到堆上的对象给我一些额外的回合（约200），但仍然崩溃。我建议以某种方式我的记忆保存变量在程序内耗尽，但是我转储的程序stacksize：
This is a related post to this one as it deals with the same program, but i now implemented it iterative and not recursive anymore, but I still get SIGSEGV (but later) while running the program. I did some other changes to my program to narrow it down, and I figured that changing a vector of objects, to a vector of ptr to the objects on the heap does give me some extra rounds (about 200), but still crashes. I suggest that somehow my memory to save variables within the program gets exhausted, but as I dump the stacksize of the program:
rlimit rlim;
getrlimit(RLIMIT_STACK,&rlim);
std::cout << "rlim_cur ist:" << rlim.rlim_cur << std::endl;
std::cout << "rlim_max ist:" << rlim.rlim_max << std::endl;
输出为：
rlim_cur ist:8388608
rlim_max ist:18446744073709551615
似乎是相当大，没有用尽，有没有任何其他相关的限制转储
进一步缩小我的问题，希望解决它？
and this seems to be pretty big and not used up, are there any other relevant limits to dumpto narrow my problem down further and hopefully solve it?
这里dump我的调试器：
Here the dump of my debugger:
Program received signal SIGSEGV, Segmentation fault.
0x000000000040b2a0 in Town::get_cur_capacity (this=0x0) at ./solver/Darstellung.cpp:98
98 return left_over_capacity;
(gdb) backtrace
#0 0x000000000040b2a0 in Town::get_cur_capacity (this=0x0) at ./solver/Darstellung.cpp:98
#1 0x000000000040b9ab in Town::compare_by_capacity (eins=0x0, zwei=0x0) at ./solver/Darstellung.cpp:135
#2 0x00000000004124c7 in std::__move_median_first<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*> >, bool (*)(Town const*, Town const*)> (__a=..., __b=..., __c=...,
__comp=0x40b98e <Town::compare_by_capacity(Town const*, Town const*)>) at /usr/include/c++/4.5/bits/stl_algo.h:108
#3 0x0000000000411250 in std::__unguarded_partition_pivot<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*> >, bool (*)(Town const*, Town const*)> (__first=..., __last=...,
__comp=0x40b98e <Town::compare_by_capacity(Town const*, Town const*)>) at /usr/include/c++/4.5/bits/stl_algo.h:2260
#4 0x000000000040f111 in std::__introsort_loop<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*> >, long, bool (*)(Town const*, Town const*)> (__first=..., __last=..., __depth_limit=21,
__comp=0x40b98e <Town::compare_by_capacity(Town const*, Town const*)>) at /usr/include/c++/4.5/bits/stl_algo.h:2302
#5 0x000000000040de63 in std::sort<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*> >, bool (*)(Town const*, Town const*)> (__first=..., __last=..., __comp=0x40b98e <Town::compare_by_capacity(Town const*, Town const*)>)
at /usr/include/c++/4.5/bits/stl_algo.h:5250
#6 0x000000000040ce5a in Solution_Stack::get_towns_by_capacity (this=0x7fffffffe010) at ./solver/Darstellung.cpp:331
#7 0x000000000040a6cf in solver::treat_towns_with_zero_capacity (ptr=0x7fffffffe010) at ./solver/Solver.cpp:184
#8 0x0000000000409ff2 in solver::solve_problem (ptr=0x7fffffffe010) at ./solver/Solver.cpp:94
#9 0x000000000041475f in main (argc=3, argv=0x7fffffffe208) at ./main/Main.cpp:50
添加检查后的新转储 - 功能追踪零值：
The new dump after adding a check-function to trace down zero values:
#0 0x000000000040b2a0 in Town::get_cur_capacity (this=0x40) at ./solver/Darstellung.cpp:98
#1 0x000000000040b9e9 in Town::compare_by_index (eins=0x40, zwei=0x73b4d0) at ./solver/Darstellung.cpp:139
#2 0x000000000040bad1 in Town::compare_by_index_inv (eins=0x40, zwei=0x73b4d0) at ./solver/Darstellung.cpp:153
#3 0x00000000004127ea in std::__unguarded_partition<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*> >, Town*, bool (*)(Town const*, Town const*)> (
__first=..., __last=..., __pivot=@0x631ef0, __comp=0x40baae <Town::compare_by_index_inv(Town const*, Town const*)>)
at /usr/include/c++/4.5/bits/stl_algo.h:2229
#4 0x0000000000411444 in std::__unguarded_partition_pivot<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*> >, bool (*)(Town const*, Town const*)> (
__first=..., __last=..., __comp=0x40baae <Town::compare_by_index_inv(Town const*, Town const*)>) at /usr/include/c++/4.5/bits/stl_algo.h:2261
#5 0x000000000040f2c5 in std::__introsort_loop<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*> >, long, bool (*)(Town const*, Town const*)> (
__first=..., __last=..., __depth_limit=7, __comp=0x40baae <Town::compare_by_index_inv(Town const*, Town const*)>)
at /usr/include/c++/4.5/bits/stl_algo.h:2302
#6 0x000000000040e017 in std::sort<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*> >, bool (*)(Town const*, Town const*)> (__first=..., __last=...,
__comp=0x40baae <Town::compare_by_index_inv(Town const*, Town const*)>) at /usr/include/c++/4.5/bits/stl_algo.h:5250
#7 0x000000000040d1e6 in Solution_Stack::get_partners_of_by_index_inv (this=0x7fffffffe010, id=523) at ./solver/Darstellung.cpp:371
#8 0x000000000040a4d7 in solver::treat_towns_considering_their_index (ptr=0x7fffffffe010) at ./solver/Solver.cpp:165
#9 0x000000000040a016 in solver::solve_problem (ptr=0x7fffffffe010) at ./solver/Solver.cpp:100
#10 0x0000000000414913 in main (argc=3, argv=0x7fffffffe208) at ./main/Main.cpp:50
Valgrind给了我这是一个转储，只是在问题曾经发生的地方反正。我对于我很困惑，由于它的大小：
Valgrind gave me this as a dump, just at the place where the problem used to occure anyways. I is quite confusing to me, due to its size:
==16150== Invalid read of size 4
==16150== at 0x40B2A0: Town::get_cur_capacity() const (Darstellung.cpp:98)
==16150== by 0x40B9AA: Town::compare_by_capacity(Town const*, Town const*) (Darstellung.cpp:135)
==16150== by 0x4124C6: void std::__move_median_first<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)>(__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)) (stl_algo.h:108)
==16150== by 0x41124F: __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > > std::__unguarded_partition_pivot<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)>(__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)) (stl_algo.h:2260)
==16150== by 0x40F110: void std::__introsort_loop<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, long, bool (*)(Town const*, Town const*)>(__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, long, bool (*)(Town const*, Town const*)) (stl_algo.h:2302)
==16150== by 0x40DE62: void std::sort<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)>(__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)) (stl_algo.h:5250)
==16150== by 0x40CE59: Solution_Stack::get_towns_by_capacity() (Darstellung.cpp:331)
==16150== by 0x40A6CE: solver::treat_towns_with_zero_capacity(Solution_Stack*) (Solver.cpp:184)
==16150== by 0x409FF1: solver::solve_problem(Solution_Stack*) (Solver.cpp:94)
==16150== by 0x41475E: main (Main.cpp:50)
==16150== Address 0x8 is not stack'd, malloc'd or (recently) free'd
==16150==
==16150==
==16150== Process terminating with default action of signal 11 (SIGSEGV)
==16150== Access not within mapped region at address 0x8
==16150== at 0x40B2A0: Town::get_cur_capacity() const (Darstellung.cpp:98)
==16150== by 0x40B9AA: Town::compare_by_capacity(Town const*, Town const*) (Darstellung.cpp:135)
==16150== by 0x4124C6: void std::__move_median_first<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)>(__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)) (stl_algo.h:108)
==16150== by 0x41124F: __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > > std::__unguarded_partition_pivot<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)>(__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)) (stl_algo.h:2260)
==16150== by 0x40F110: void std::__introsort_loop<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, long, bool (*)(Town const*, Town const*)>(__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, long, bool (*)(Town const*, Town const*)) (stl_algo.h:2302)
==16150== by 0x40DE62: void std::sort<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)>(__gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, __gnu_cxx::__normal_iterator<Town**, std::vector<Town*, std::allocator<Town*> > >, bool (*)(Town const*, Town const*)) (stl_algo.h:5250)
==16150== by 0x40CE59: Solution_Stack::get_towns_by_capacity() (Darstellung.cpp:331)
==16150== by 0x40A6CE: solver::treat_towns_with_zero_capacity(Solution_Stack*) (Solver.cpp:184)
==16150== by 0x409FF1: solver::solve_problem(Solution_Stack*) (Solver.cpp:94)
==16150== by 0x41475E: main (Main.cpp:50)
==16150== If you believe this happened as a result of a stack
==16150== overflow in your program's main thread (unlikely but
==16150== possible), you can try to increase the size of the
==16150== main thread stack using the --main-stacksize= flag.
==16150== The main thread stack size used in this run was 8388608.
==16150==
==16150== HEAP SUMMARY:
==16150== in use at exit: 771,174 bytes in 19,239 blocks
==16150== total heap usage: 9,821,251 allocs, 9,802,012 frees, 384,861,557 bytes allocated
==16150==
==16150== 50,678 bytes in 1,491 blocks are possibly lost in loss record 28 of 35
==16150== at 0x4C28B42: operator new(unsigned long) (vg_replace_malloc.c:261)
==16150== by 0x4ECBE6C: std::string::_Rep::_S_create(unsigned long, unsigned long, std::allocator<char> const&) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.14)
==16150== by 0x4ECC08D: std::string::_M_mutate(unsigned long, unsigned long, unsigned long) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.14)
==16150== by 0x4ECC730: std::string::erase(unsigned long, unsigned long) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.14)
==16150== by 0x407FB6: utility::split_helper(std::string, std::string) (Tools.cpp:28)
==16150== by 0x4080B5: utility::split_helper(std::string, std::string) (Tools.cpp:49)
==16150== by 0x4081C3: utility::split(std::string, std::string) (Tools.cpp:66)
==16150== by 0x40539C: parser::get_city_prototypes(std::vector<std::string, std::allocator<std::string> >) (Parser.cpp:27)
==16150== by 0x4050EB: parser::get_problem_configuration(std::string, std::string) (Parser.cpp:17)
==16150== by 0x414699: main (Main.cpp:34)
==16150==
==16150== 62,606 (11,928 direct, 50,678 indirect) bytes in 1,491 blocks are definitely lost in loss record 30 of 35
==16150== at 0x4C28B42: operator new(unsigned long) (vg_replace_malloc.c:261)
==16150== by 0x407F68: utility::split_helper(std::string, std::string) (Tools.cpp:24)
==16150== by 0x4080B5: utility::split_helper(std::string, std::string) (Tools.cpp:49)
==16150== by 0x4081C3: utility::split(std::string, std::string) (Tools.cpp:66)
==16150== by 0x40539C: parser::get_city_prototypes(std::vector<std::string, std::allocator<std::string> >) (Parser.cpp:27)
==16150== by 0x4050EB: parser::get_problem_configuration(std::string, std::string) (Parser.cpp:17)
==16150== by 0x414699: main (Main.cpp:34)
==16150==
==16150== 94,406 (18,440 direct, 75,966 indirect) bytes in 2,305 blocks are definitely lost in loss record 32 of 35
==16150== at 0x4C28B42: operator new(unsigned long) (vg_replace_malloc.c:261)
==16150== by 0x407F68: utility::split_helper(std::string, std::string) (Tools.cpp:24)
==16150== by 0x4080B5: utility::split_helper(std::string, std::string) (Tools.cpp:49)
==16150== by 0x4081C3: utility::split(std::string, std::string) (Tools.cpp:66)
==16150== by 0x40573F: parser::get_finished_cities(std::vector<std::string, std::allocator<std::string> >, std::vector<City*, std::allocator<City*> >) (Parser.cpp:42)
==16150== by 0x40511A: parser::get_problem_configuration(std::string, std::string) (Parser.cpp:17)
==16150== by 0x414699: main (Main.cpp:34)
==16150==
==16150== 178,720 (131,208 direct, 47,512 indirect) bytes in 1,491 blocks are definitely lost in loss record 35 of 35
==16150== at 0x4C28B42: operator new(unsigned long) (vg_replace_malloc.c:261)
==16150== by 0x40541B: parser::get_city_prototypes(std::vector<std::string, std::allocator<std::string> >) (Parser.cpp:28)
==16150== by 0x4050EB: parser::get_problem_configuration(std::string, std::string) (Parser.cpp:17)
==16150== by 0x414699: main (Main.cpp:34)
==16150==
==16150== LEAK SUMMARY:
==16150== definitely lost: 161,576 bytes in 5,287 blocks
==16150== indirectly lost: 174,156 bytes in 5,287 blocks
==16150== possibly lost: 50,678 bytes in 1,491 blocks
==16150== still reachable: 384,764 bytes in 7,174 blocks
==16150== suppressed: 0 bytes in 0 blocks
==16150== Reachable blocks (those to which a pointer was found) are not shown.
==16150== To see them, rerun with: --leak-check=full --show-reachable=yes
==16150==
==16150== For counts of detected and suppressed errors, rerun with: -v
==16150== Use --track-origins=yes to see where uninitialised values come from
==16150== ERROR SUMMARY: 7 errors from 7 contexts (suppressed: 4 from 4)
推荐答案
#0 0x000000000040b2a0 in Town::get_cur_capacity (this=0x0) at ./solver/Darstellung.cpp:98
看起来你在NULL指针上调用 get_cur_capacity 。
It looks like you're invoking get_cur_capacity on a NULL pointer. You're getting here from a comparator:
#1 0x000000000040b9ab in Town::compare_by_capacity (eins=0x0, zwei=0x0) at ./solver/Darstellung.cpp:135
这是将NULL与NULL比较。您还可以从排序进一步到达这里：
which is comparing NULL to NULL. You further get here from a sort:
#5 0x000000000040de63 in std::sort<__gnu_cxx::__normal_iterator<Town**, std::vector<Town*> >, bool (*)(Town const*, Town const*)> (__first=..., __last=..., __comp=0x40b98e <Town::compare_by_capacity(Town const*, Town const*)>)
at /usr/include/c++/4.5/bits/stl_algo.h:5250
这是排序 std :: vector&
This is sorting std::vector<Town*>, and is called from:
#6 0x000000000040ce5a in Solution_Stack::get_towns_by_capacity (this=0x7fffffffe010) at ./solver/Darstellung.cpp:331
NULL指针，并且您的 compare_by_capacity 函数不准备处理这种可能性。要么确保向量没有NULL，要么 compare_by_capacity 显式检查 NULL 并做一些明智的事情
Most likely the vector you're sorting contains NULL pointers, and your compare_by_capacity function is not prepared to handle this eventuality. Either make sure the vector has no NULLs, or have compare_by_capacity explicitly check for NULL and do something sensible (eg, sort it before anything other than another NULL).
#1 0x000000000040b9e9 in Town::compare_by_index (eins=0x40, zwei=0x73b4d0) at ./solver/Darstellung.cpp:139
此 0x40 看起来像你有未初始化的内存或损坏的内存。如何调整此向量的大小？
This 0x40 looks like you have either uninitialized memory or corrupted memory. How are you resizing this vector?
这真的很难尝试诊断，而实际上没有看到任何代码。
It's really quite difficult to try to diagnose this without actually seeing any of your code.
这篇关于SIGSEGV在std :: sort中，如何缩小它的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！