C 中上下文中的 Valgrind 错误

Question

我遇到了这个错误，但找不到原因，这是一个项目，我不能在这里真正显示源代码，但我是这样分配内存的：

if(!data_counter)
    lab=(ptr)malloc(sizeof(item));
else
    lab=(ptr)realloc(lab,sizeof(item)*(DC+1));

我一直在 Valgrind 中获取此日志，即使我的代码可以完美编译和运行。
我觉得我重新分配了内存错误。 sizeof(item) 中的项目也是一个有 4 个字段的结构

==18449==   
==18449== HEAP SUMMARY:  
==18449==     in use at exit: 352 bytes in 1 blocks  
==18449==   total heap usage: 15 allocs, 14 frees, 4,416 bytes allocated  
==18449==   
==18449== Searching for pointers to 1 not-freed blocks  
==18449== Checked 69,180 bytes  
==18449==   
==18449== LEAK SUMMARY:  
==18449==    definitely lost: 0 bytes in 0 blocks  
==18449==    indirectly lost: 0 bytes in 0 blocks  
==18449==      possibly lost: 0 bytes in 0 blocks  
==18449==    still reachable: 352 bytes in 1 blocks  
==18449==         suppressed: 0 bytes in 0 blocks  
==18449== Reachable blocks (those to which a pointer was found) are not shown.  
==18449== To see them, rerun with: --leak-check=full --show-reachable=yes  
==18449==   
==18449== Use --track-origins=yes to see where uninitialised values come from  
==18449== ERROR SUMMARY: 4 errors from 3 contexts (suppressed: 0 from 0)  
==18449==   
==18449== 1 errors in context 1 of 3:  
==18449== Conditional jump or move depends on uninitialised value(s)  
==18449==    at 0x804B960: checkLabel (12.c:797)  
==18449==    by 0x8048B55: line_parser (12.c:132)  
==18449==    by 0x8048914: file_parser (12.c:108)  
==18449==    by 0x804C5CE: main (12.c:995)  
==18449==   
==18449==   
==18449== 1 errors in context 2 of 3:  
==18449== Conditional jump or move depends on uninitialised value(s)  
==18449==    at 0x804BC24: checkLabel (12.c:836)  
==18449==    by 0x8048B55: line_parser (12.c:132)  
==18449==    by 0x8048914: file_parser (12.c:108)  
==18449==    by 0x804C5CE: main (12.c:995)  
==18449==   
==18449==   
==18449== 2 errors in context 3 of 3:    
==18449== Conditional jump or move depends on uninitialised value(s)  
==18449==    at 0x804BE61: update_labl_adrr (12.c:883)  
==18449==    by 0x804C720: main (12.c:1014)  
==18449==   
==18449== ERROR SUMMARY: 4 errors from 3 contexts (suppressed: 0 from 0)

任何帮助将不胜感激

Answer 1

如果您指的是 Conditional jump or move depends on uninitialized value(s) 错误，这意味着您的条件包含未初始化的值。

这可以是 while、for、if 或 switch 语句中的条件。从 Valgrind 回溯中，您可以看出 checkLabel 和 update_labl_adrr 中有一些流程控制语句，但由于我们看不到该代码，因此很难说出其他任何内容。

使用递归结构（即链表、树等）时的一个常见错误是没有将 next/child 指针初始化为 NULL。这通常会导致您发布错误。但是，这完全是猜测，因为我们对您的代码一无所知。
至少，如果不了解 checkLabel 和 update_labl_addr

中的内容，就无法进一步提供帮助

C 中上下文中的 Valgrind 错误

Valgrind errors in context in C

c

valgrind