c -为什么我在这里得到一个分割错误

Question

#include <stdio.h>
#include <pthread.h>
#include <time.h>
#include <stdlib.h>
typedef struct pr_struct{
    int owner;
    int burst_time;
    struct pr_struct *next_prcmd;
} prcmd_t;
static prcmd_t *pr_head = NULL;
static prcmd_t *pr_tail = NULL;
static int pending_request = 0;
static pthread_mutex_t prmutex = PTHREAD_MUTEX_INITIALIZER;

int add_queue(prcmd_t *node)
{       
    pthread_mutex_lock(&prmutex);
    //code
    prcmd_t *curNode = pr_head;
    if(pr_head == NULL) { pr_head = node; return;}
    while(curNode->next_prcmd)
    {
         curNode->next_prcmd = (prcmd_t*)malloc(sizeof(prcmd_t));   
         curNode = curNode->next_prcmd;
    }
    curNode->next_prcmd = node;
    //
    pending_request++;
    pthread_mutex_unlock(&prmutex);
    return(0);
}

int main()
{
    if (pr_head == NULL)
    {
        printf("List is empty!n");
    }
    prcmd_t *pr1;
    pr1->owner = 1;
    pr1->burst_time = 10;
    add_queue(pr1);
    prcmd_t *curNode = pr_head;
    while(curNode->next_prcmd)
    {
        printf("%in", curNode->owner);
        curNode = curNode->next_prcmd;
    }
}

编辑:

这是我现在的…

int main()
{

prcmd_t *pr1;
pr1 = (prcmd_t*)malloc(sizeof(prcmd_t));
pr1->owner = 1;
pr1->burst_time = 10;

if (pr_head == NULL)
{
    printf("List is empty!n");
}
add_queue(pr1);

prcmd_t *curNode = pr_head;
printf("made it here 1n");
while(curNode->next_prcmd)
{
    printf("in the while loopn");
    printf("%in", curNode->owner);
    curNode = curNode->next_prcmd;
}
}

输出是:列表为空!1

Answer 1

pr1是指向prcmd_t struct的未初始化指针，解引用未初始化的指针会导致未定义行为。

你需要在堆/堆栈上为结构分配空间(取决于它将被使用的位置)，所以一个选项是:

// Allocate on stack
prcmd_t pr1;
pr1.owner = 1;
pr1.burst_time = 10;
add_queue(&pr1);

，第二个是:

//Allocae on heap
prcmd_t *pr1;
pr = (prcmd_t*)malloc(sizeof(prcmd_t));
pr1->owner = 1;
pr1->burst_time = 10;
add_queue(pr1);

将你的main方法修改为

int main()
{
    if (pr_head == NULL)
    {
        printf("List is empty!n");
    }
    prcmd_t *pr1;   
    pr1 = (prcmd_t*)malloc(sizeof(prcmd_t));
    pr1->owner = 1;
    pr1->burst_time = 10;
    add_queue(pr1);
    prcmd_t *curNode = pr_head;
    while(curNode && curNode->owner)
    {
        printf("%in", curNode->owner);
        curNode = curNode->next_prcmd;
    }
}

输出

List is empty!
1

Answer 2

如果你不告诉我们在哪里，我们很难判断…

,

• 必须初始化节点->next_prcmd为null
为什么在while循环中使用malloc ?你是从而摧毁你的当前->下一个，下一个迭代哪个好看坏…

马里奥