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我希望4個線程將進入名爲read
的同一個函數,並執行函數中的內容(在監視器上打印之後進行讀取,以及以顯示所有...)。 問題:多線程程序中的核心轉儲:basic_string :: _ S_construct null無效
terminate called after throwing an instance of 'std::logic_error'
what(): basic_string::_S_construct null not valid
trAborted (core dumped)
的代碼是:
#include <pthread.h>
#include <unistd.h>
#include <stdio.h>
#include <iostream>
#include <time.h>
#include <cstdlib>
#include <fstream>
#include <string>
using namespace std;
struct v {
int id;
char* ad;
v(int a, char* t) {
id = a;
ad = t;
}
};
int bank = 1000;
pthread_mutex_t mutex;
void* read(void* argument)
{
cout << "tr";
v* d;
int num;
d = (v*) argument;
string l = d->ad;
int n = d->id;
string x = "";
ifstream textfile;
textfile.open(l.c_str());
while (!textfile.eof()) {
textfile >> x;
if (x == "SUB") {
pthread_mutex_lock(&mutex);
textfile >> num;
bank = bank - num;
cout << "person num " << n << " sub " << num << " dollars and know in the Bank: " << bank << endl;
pthread_mutex_unlock(&mutex);
}
if (x == "ADD") {
pthread_mutex_lock(&mutex);
textfile >> num;
bank = bank + num;
cout << "person num " << n << " add " << num << " dollars and know in the Bank: " << bank << endl;
pthread_mutex_unlock(&mutex);
}
if (x == "GET") {
pthread_mutex_lock(&mutex);
cout << "person num " << n << " look in the Bank: " << bank << endl;
pthread_mutex_unlock(&mutex);
}
}
textfile.close();
return 0;
}
int main(void)
{
pthread_mutex_init(&mutex, NULL);
int i = 0, j = 0;
v data1(1, "file1.dat"), data2(2, "file2.dat"), data3(3, "file3.dat"), data4(4, "file4.dat");
pthread_t t1, t2, t3, t4;
i = pthread_create(&t1, NULL, read, (void*)&data1);
if (i != 0) cout << "error" ;
j = pthread_create(&t2, NULL, read, (void*)&data2);
if (j != 0) cout << "error" ;
i = pthread_create(&t3, NULL, read, (void*)&data3);
if (i != 0) cout << "error" ;
j = pthread_create(&t4, NULL, read, (void*)&data4);
if (j != 0) cout << "error" ;
pthread_exit(NULL);
return 0;
}
通過用try/catch連續包裝程序中越來越小的部分來做分而治之,直到找出哪個語句正在拋出。另外:什麼操作系統,編譯器,編譯器的版本號,也許最重要的是libc的版本?它可能不是答案,但在一些較舊的Gnu libcs中,字符串構造函數不是線程安全的(它們在實現中深處共享一個未同步的單例)。 – 2013-05-03 15:03:00
請不要在覈心轉儲錯誤之前發佈問題,直到您告訴我們錯誤的行號。你真的希望我們爲你編譯和調試嗎?告訴我們哪一行是問題。 (如果你不知道該怎麼做,那麼在編寫超過10行的程序之前,請學會使用gdb,運行「gdb ./myprog」,並在使用堆棧跟蹤調用終止時停止。) – 2013-05-03 17:00:41
@NicholasWilson:我同意(我們需要行號),但這是一個未捕獲的異常,所以在終止時堆棧已經完全解除。那麼gdb會給出任何有用的信息?這就是爲什麼我提出了分而治之的嘗試捕捉方法。 – 2013-05-03 17:48:38