从链接列表中检索消息,然后从列表中删除该消息会导致分段错误。从链接列表中获取并从链接列表中删除结果出现分段错误
第一条消息和服务器消息的结构:
// used to store messages.
struct server_message {
char message[80];
char id[80];
struct server_message *next_msg;
};
//head of the list
static struct server_message *first_message = NULL;
Get消息功能
char *get_message(char *id) {
char *message;
char *not_found =(char *) malloc(sizeof(char) * 20);
not_found = "No messages available";
struct server_message *curr_msg = first_message;
struct server_message *prev_msg = first_message;
if (curr_msg != NULL && (strcmp(curr_msg->id, id) != 0)) {
strcpy (message, curr_msg->message);
//Remove message
first_message = NULL;
return message;
}
while (curr_msg->next_msg != NULL) {
curr_msg = curr_msg->next_msg;
if (strcmp(curr_msg->id, id) != 0) {
strcpy (message, curr_msg->message);
//Remove message
prev_msg->next_msg = curr_msg->next_msg;
return message;
} else {
prev_msg = curr_msg;
}
}
return not_found;
}
更新代码仍然赛格断层
char *get_message(char *id) {
char *message = (char *) malloc(sizeof(char) * 80);
char *not_found=(char *) malloc(sizeof(char) * 20);
strcpy(not_found, "No messages available");
struct server_message *curr_msg = first_message;
struct server_message *prev_msg = NULL;
while (curr_msg->next_msg != NULL) {
if (strcmp(curr_msg->id, id) != 0) {
strcpy (message, curr_msg->message);
//Remove message
if (prev_msg == NULL) {
first_message = curr_msg->next_msg;
} else {
prev_msg->next_msg = curr_msg->next_msg;
}
return message;
} else {
prev_msg = curr_msg;
curr_msg = curr_msg->next_msg;
}
}
return not_found;
}
调试器....................... –
此代码严重损坏。内存泄漏,未初始化指针的解引用等等。只是一对夫妇:(1)'message'永远不会被初始化,然而你试图存储它。分段故障。 (2)''not_found'被设置为从'malloc'存储。但是在这个存储被使用之前,'not_found'立即被设置为一个常量字符串。内存泄漏。我相信还有更多。这看起来更像是一个不知道C的问题,而不是寻找错误。 –
@TomKarzes对于消息我可以使用'char消息[80]'? –