双链表实现中的"Conditional jump or move depends on uninitialised value"

"Conditional jump or move depends on uninitialised value" in double linked list implementation

本文关键字：move depends on value uninitialised or Conditional 实现 链表 jump      更新时间：2023-10-16

Valgrind告诉我两个我无法解决的错误。我得到一个"有条件的跳转或移动取决于未初始化的值"错误信息在以下函数unplug_set。是因为NULL支票的原因吗?该函数应该从双链表中拔出一个元素。

void unplug_set(set * set_to_unplug){
        set * last_set = set_to_unplug->last;
        set * next_set = set_to_unplug->next;
        set_to_unplug->next = NULL;
        set_to_unplug->last = NULL;
148     if(last_set == NULL && next_set == NULL){ // only one element left
          ordered_by_score_set[set_to_unplug->weight] = NULL;
150     }else if(last_set == NULL){ // first set
          next_set->last = NULL;
          ordered_by_score_set[set_to_unplug->weight] = next_set;
        } else if (next_set == NULL) { // last set
          last_set->next = NULL;
        } else { // set in the middle
          last_set->next = next_set;
        next_set->last = last_set;
       }
}
Valgrind命令: 
valgrind --dsymutil=yes --track-origins=yes ./set_program
输出:

==45085== Conditional jump or move depends on uninitialised value(s)
==45085==    at 0x100001A2C: unplug_set(set*) (:148)
                          ...
==45085==    by 0x100001294: main (Main.cpp:81)
==45085==  Uninitialised value was created by a heap allocation
==45085==    at 0xC713: malloc (vg_replace_malloc.c:274)
==45085==    by 0x63346: operator new(unsigned long) (in /usr/lib/libstdc++.6.0.9.dylib)
==45085==    by 0x100001E0C: add_set(int, int, unsigned int const*, unsigned short const*, int, unsigned int const*) (:57)
==45085==    by 0x10000127E: main (Main.cpp:39)
==45085==
==45085== Conditional jump or move depends on uninitialised value(s)
==45085==    at 0x100001A60: unplug_set(set*) (:150)
                          ...
==45085==    by 0x100001294: main (Main.cpp:81)
==45085==  Uninitialised value was created by a heap allocation
==45085==    at 0xC713: malloc (vg_replace_malloc.c:274)
==45085==    by 0x63346: operator new(unsigned long) (in /usr/lib/libstdc++.6.0.9.dylib)
==45085==    by 0x100001E0C: add_set(int, int, unsigned int const*, unsigned short const*, int, unsigned int const*) (:57)
==45085==    by 0x10000127E: main (Main.cpp:39)

set_to_unplug参数值由其构造函数使用new操作符初始化。如果构造函数中没有初始化，那么你就有了valgrind报错的原因。

我们没有足够的资料来回答你的问题。张贴如何使用此功能。以及如何初始化参数值
相关文章：