当我使用valgrind时,我在代码中反复收到以下错误.我不太确定这些意思是什么,我无法确定未初始化的值.
==16795== Conditional jump or move depends on uninitialised value(s)
==16795== at 0x4A06E8A: strcmp (mc_replace_strmem.c:412)
==16795== by 0x4009C7: dictionary_add (libdictionary.c:44)
==16795== by 0x40061B: main (part2.c:28)
==16795==
==16795== Invalid write of size 1
==16795== at 0x4A082E7: strcpy (mc_replace_strmem.c:303)
==16795== by 0x400AA8: dictionary_add (libdictionary.c:57)
==16795== by 0x40061B: main (part2.c:28)
==16795== Address 0x4c361a3 is 0 bytes after a block of size 3 alloc'd
==16795== at 0x4A05E1C: malloc (vg_replace_malloc.c:195)
==16795== by 0x400931: node_newnode (libdictionary.c:28)
==16795== by 0x400A8C: dictionary_add (libdictionary.c:54)
==16795== by 0x40061B: main (part2.c:28) …我正在学习C的基础知识,现在正在使用malloc().假设我有一个函数要求用户输入,用一个数据填充一个结构,并保存在一个数组中(所有结构都通过main函数引用传递).
我通过Valgrind运行程序,我得到"仍然可以访问"的字节(这应该是正确的？不被认为是泄漏),但是任何保存的数据我都会丢失块.
程序运行完成后,如何释放内存？此外,我在代码中有一些(2)问题只是为了澄清一些事情,如果有人可以向我解释,我会很感激.
这是一些类似于我想要做的代码:
我声明了以下结构:
struct Person {
char name[MAX_INPUT];
int age;
};
我正在写一个像这样的函数:
int function2(struct Person *list, int *index) {
struct Person *prsn = malloc(sizeof(struct Person));
// !Why do we sometimes cast the malloc or not?
// I sometimes get errors when I do, sometimes when I don't,
// while the surrounding code is pretty much the same.
assert(prsn != NULL);
// User input code goes here ...
// Now to save the Person created
strcpy(prsn->name, nameInput);
prsn->age = …我在valgrind中遇到错误,不知道出了什么问题.错误是:valgrind输出:
Run Code Online (Sandbox Code Playgroud)==1112== Conditional jump or move depends on uninitialised value(s) ==1112== at 0x402BF0D: realloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
并且它表明问题发生在第226行:
if(reallocate ==TRUE)
{
char** temp_values = NULL;
temp_values = (char**) realloc(theBoard->_values, theBoard->_size_r*sizeof(char*) );
if(temp_values!=NULL)
{
theBoard->_values = temp_values;
} else
{
reportError(MEM_OUT);
return FALSE;
}
int i = 0;
for (i=0; i<theBoard->_size_r; i++)
{
char* temp_values_c = NULL;
HERE( line 226)-> temp_values_c = realloc(theBoard->_values[i], theBoard->_size_c*sizeof(char) );
if(temp_values_c != NULL)
{
theBoard->_values[i] = temp_values_c;
} else
{
reportError(MEM_OUT);
return FALSE;
}
}
// initialize …我有以下程序:
#include <stdio.h>
#include <stdlib.h>
typedef struct a{
int a;
} Player;
typedef struct b{
Player players[5];
}* Formation;
int main()
{
Player a; a.a = 1;
Player b; b.a = 2;
Player c; c.a = 3;
Player d; d.a = 4;
Player e; e.a = 5;
Formation team = malloc(sizeof(*team));
team->players[0] = a;
team->players[1] = b;
team->players[2] = c;
team->players[3] = d;
team->players[4] = e;
for (int i = 0; i < 5; i++){
team->players[i] = team->players[i + 1]; …我使用new在堆上分配了一个向量:
std::vector<t*> *vec = new std::vector<t*>;
此向量包含类"t"的类对象,这些类对象是使用new创建的
t *ptr1 = new t();
t *ptr2 = new t();
t *ptr3 = new t();
t *ptr4 = new t();
现在,当我删除矢量时,预计添加到它的所有这些对象也应该被销毁,我的意思是:
std::vector<t*> *vec = new std::vector<t*>;
vec->push_back(ptr1);
vec->push_back(ptr2);
vec->push_back(ptr3);
vec->push_back(ptr4);
ptr1指向的内存,ptr2,ptr3,ptr4也应该被释放.
但是Valgrind将此视为泄漏!!! Valgrind有问题吗？
==15634==
==15634== HEAP SUMMARY:
==15634== in use at exit: 48 bytes in 8 blocks
==15634== total heap usage: 12 allocs, 4 frees, 128 bytes allocated
==15634==
==15634== LEAK SUMMARY:
==15634== definitely lost: 32 bytes in 4 blocks
==15634== indirectly lost: …我用"valgrind --leak-check = full"测试了我的软件,它显示:
==90862== 7,627 bytes in 4 blocks are definitely lost in loss record 858 of 897
==90862== at 0x4C2FB55: calloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==90862== by 0xD64991C: concat(int, ...) (Client.cpp:150)
我无法理解为什么,因为我在calloc之后使用free().这是我的代码:
char* p = concat(2, buffOld, buff);
char *x;
while(true) {
x = p;
p = strstr(p,"\\final\\");
if(p == NULL) { break; }
*p = 0;
p+=7;
parseIncoming((char *)x,strlen(x));
}
free(p);
而"concat"功能:
char* concat(int count, ...)
{
va_list ap;
int i;
// Find required length to store merged string …我有一段非常简单的代码:
#include <iostream>
int main()
{
int *val = new int;
*val = 12;
std::cout << *val << std::endl;
delete &val;
return 0;
}
当我在这上面运行Valgrind时,我收到以下错误:
SUMMARY: 3 errors from 3 contexts (suppressed: 8 from 8)
1 errors in context 1 of 3:
Invalid free() / delete / delete[] / realloc()
at 0x1000ABB6D: free (vg_replace_malloc.c:533)
by 0x100000D1E: main (pointers.cpp:8)
Address 0x1048a09f0 is on thread 1's stack
in frame #1, created by main (pointers.cpp:4)
我如何删除有val什么问题？
我正在创建一个c++具有两种略有不同的方式的对象,在以下代码CASE中0存在内存泄漏,但在这种else情况下没有内存泄漏.
#include <string>
#define CASE 1
class A {
private:
std::string *s;
public:
A(std::string *p_s) { s = p_s; }
};
int main() {
#if CASE==0
auto a = A(new std::string("Hello"));
#else
auto s = std::string("Hello");
auto a = A(&s);
#endif
}
当我设置CASE 0了valgrind说有内存泄漏
valgrind ./a.out
==24351== Memcheck, a memory error detector
==24351== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==24351== Using Valgrind-3.13.0 and … struct node {
int data;
struct node *next;
};
int main() {
struct node *head = malloc(sizeof(struct node));
struct node *current = head;
...
};
虽然这段代码可以在没有任何警告或错误的情况下运行,但Valgrind会给出一些消息Conditional jump or move depends on uninitialised value(s),Uninitialised value was created by a heap allocation
我无法弄清楚出了什么问题.我们在node函数外定义了一个struct main.所以我认为我们可以使用sizeof(struct node),不是吗？
作为一个项目，我正在创建一个学生数据库。但是根据valgrind，我的程序中存在内存泄漏，我不知道为什么。我真的不能说太多：我不明白为什么记忆肯定会丢失。
学生结构：
typedef struct {
char student_number[7];
char *first_name;
char *last_name;
int round_points[6];
} Student;
免责声明：我正在使用gcc选项-std=c99，因此必须实现自己的strdup()。
重要的代码段：
char *copy_string(const char *string) {
int len = strlen(string);
char *copy = calloc(len + 1, sizeof(char));
if (copy == NULL)
return NULL;
strcpy(copy, string);
/* copy[len] = '\0'; */
return copy;
}
char **parse_one_line_params(const char *one_line, int param_count) {
char *copy = copy_string(one_line);
if (copy == NULL)
return NULL;
//copy_start is used to free the copy string in the …