我遇到了错误“undefined reference to `pthread_attr_init'”，尽管这个函数应该在pthread.h中。这是在一个应该设置为Pthreads的UNIX环境中发生的。另外，使用void*指向当前矩阵是一个好方法吗？以下是我的代码，请问有什么建议吗？
#include <cstdlib>
#include <iostream>
#include <sstream>
#include <string>
#include <vector>
#include <time.h>
#include <limits.h>
#include <pthread.h>
#include <semaphore.h>
#define MAX_MATRIX_SIZE 256
#define MAX_THREADS 64
using namespace std;
void *StripProcessor(void *);
void Barrier();
void InitMatrix(int rows, int cols);
int main(int argc, char *argv[])
{
/* Get command line params */
if (argc != 3) {
cout << "Error: need 2 command line params." << endl;
getchar();
return 1;
}
int numThreads = atoi(argv[1]);
double epsilon = atof(argv[2]);
/* Locals hang here */
pthread_mutex_t barrier;
pthread_cond_t leave;
int numWaiting = 0;
int rows;
int cols;
int stripSize;
int lastStripSize;
int iterations;
double matrix1[MAX_MATRIX_SIZE][MAX_MATRIX_SIZE];
double matrix2[MAX_MATRIX_SIZE][MAX_MATRIX_SIZE];
void *currentMatrix = matrix1; //????????????????
double stripMaxDiff[MAX_THREADS];
clock_t start;
clock_t finish;
/* Get rows and cols from standard in */
string buffer;
getline(cin, buffer);
istringstream myStream(buffer);
myStream >> rows;
myStream >> cols;
cout << rows << " " << cols << endl;
getchar();
/* Set locals */
if (rows % numThreads == 0) {
stripSize = rows / numThreads;
lastStripSize = 0;
}
else {
stripSize = rows / numThreads + 1;
if (rows % stripSize == 0) {
numThreads = rows / stripSize;
lastStripSize = 0;
}
else {
numThreads = rows / stripSize + 1;
lastStripSize = rows - (stripSize * (numThreads - 1));
}
}
/* Set up threads */
vector<pthread_t> threadID;
pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM);
/* Init mutex, CV, and matrix */
pthread_mutex_init(&barrier, NULL);
pthread_cond_init(&leave, NULL);
//InitMatrix(rows, cols);
/* Create threads and wait for completion */
start = clock();
/*for (unsigned int i = 0; i < threadID.size; i++)
pthread_create(&threadID[i], &attr, StripProcessor, (void *) i);
for (unsigned int i = 0; i < threadID.size; i++)
pthread_join(threadID[i], NULL);*/
finish = clock();
/* Print results */
}