使用pthread和代码甚至无法进入main方法

Question

我正在做一个学校作业，应该并行执行以下代码（该代码生成带有Buddhabrot分形的pgm图像）。 问题是编译器没有指出任何错误，而且代码甚至都无法进入主程序。 我已经尝试过查找它，但是没有找到解决方法。

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <pthread.h>
#define NT 3

int nColumns, nLines, size, ite, proximo;
double dt, x, y;
float **mat;

pthread_mutex_t mutex;
pthread_cond_t condM;
pthread_cond_t condE;

typedef struct {
    int x;
    int y;
} int2;

typedef struct{
    double x;
    double y;
} double2;

int2 coordinatesConversion(double x,double y, int nColumns,int nLines){
    int2 ret;
    int2 retError;
    retError.x=-1;
    retError.y=-1;
    ret.x=round(((2.0+x)/3.5) *((double)(nColumns-1)));
    ret.y=round(((1.5+y)/3.5) *((double)(nLines-1)));
    if(ret.x<0 || ret.x>=nColumns) return retError;
    if(ret.y<0 || ret.y>=nLines) return retError;
    return ret;
}

int printMatrixToFilePGM(float **mat,int tamx, int nLines, char *srcFile){
    FILE *arq=fopen(srcFile,"w");
    int cont, cont2;
    float min,max; 
    min=mat[0][0];
    max=mat[0][0];
    for(cont=0;cont<nLines;cont++) 
        for(cont2=0;cont2<tamx;cont2++){
            if(min>mat[cont][cont2]) min=mat[cont][cont2];
            if(max<mat[cont][cont2]) max=mat[cont][cont2];
        }

    max=max*0.35;
    float delta = max-min;
    fprintf(arq,"P2 \n");
    fprintf(arq,"%d\n%d \n",tamx,nLines);
    fprintf(arq,"255\n");
    for(cont=0;cont<nLines;cont++)
        for(cont2=0;cont2<tamx;cont2++){ 
            int valpixel=((mat[cont][cont2]-min)/delta)*255.0f;
            if(valpixel>255) valpixel=255;
            fprintf(arq,"%d \n", valpixel);
        } 
    fclose(arq);
}

float** mallocFloatMatrix(int tamx, int nLines, float defaultValueOfTheElementsAtMatrix){
    float **errorCodeReturn=0x0;
    float **mat;
    int i,j;
    int condErrorMalloc=0;
    mat=malloc(sizeof(float *)*nLines);
    if(mat==0x0) return errorCodeReturn;
    for(i=0;i<tamx;i++) mat[i]=malloc(sizeof(float )*tamx);
    for(i=0;i<tamx;i++)
        if(mat[i]==0x0){
            condErrorMalloc=1;
            break;
        }

    if(condErrorMalloc==0) return mat;
    for(i=0;i<nLines;i++) for(j=0;j<tamx;j++) mat[i][j]=defaultValueOfTheElementsAtMatrix;
    for(i=0;i<tamx;i++) if(mat[i]!=0x0) free(mat[i]);
    free(mat);
    return errorCodeReturn;
}

void freeFloatMatrix(float **mat,int tamx, int nLines){
    int i;
    for(i=0;i<nLines;i++) if(mat[i]!=0x0) free(mat[i]);
    free(mat);
}

int iteration(double x,double y, int nColumns,int nLines, int ite,int2 *iterationPath){
    int cont;    
    int condInvalidPointer=1;
    double2 z;
    z.x=0.0;
    z.y=0.0;
    double2 c;
    c.x=x;
    c.y=y;
    double2 zt;
    for(cont=0;cont<ite;cont++){
        zt.x=((z.x*z.x)-(z.y*z.y))+c.x;
        zt.y=(2.0*(z.x*z.y))+c.y;
        z=zt;
        if(((z.x*z.x)+(z.y*z.y))>4.0){
            if(cont>100) condInvalidPointer=0;
            break;
        }
        iterationPath[cont]=coordinatesConversion(z.x,z.y,nColumns,nLines);
    }
    if(condInvalidPointer) return 0;
    return cont;
}

void *mestre(void *param) {
    int i;
    for(i=0;i<size;i++){
        x = -2.0+((double)i*dt);
        for(y=-2.0;y<2.0;y=y+dt){
            pthread_mutex_lock(&mutex);
            proximo++;
            pthread_cond_signal(&condE);
            pthread_cond_wait(&condM, &mutex);
            pthread_mutex_unlock(&mutex);
        }
    }
}

void *escravo(void *param) {
    pthread_mutex_lock(&mutex);
    if(proximo==0) pthread_cond_wait(&condE, &mutex);
    double xe = x;
    double ye = y;
    proximo--;
    pthread_cond_signal(&condM);
    pthread_mutex_unlock(&mutex);
    int k;
    int2* iterationPath = (int2 *)malloc(sizeof(int2)*ite);
    if(iterationPath==0x0) return 0x0;
    int completedIterations = iteration(xe, ye, nColumns, nLines, ite, iterationPath);
    for(k=0;k<completedIterations;k++){
        if(iterationPath[k].x!=-1 && iterationPath[k].y!=-1)
            mat[iterationPath[k].x][iterationPath[k].y]=mat[iterationPath[k].x][iterationPath[k].y]+1.0f;
    }
    free(iterationPath);
}

int main(void){

    printf("Main method has started.");

    pthread_mutex_init(&(mutex), NULL);
    pthread_cond_init(&(condM), NULL);
    pthread_cond_init(&(condE), NULL);

    nColumns=2048;
    nLines=2048;
    dt=0.001;
    size=round(4.0/dt);
    ite=600;
    proximo = 0;

    mat=mallocFloatMatrix(nColumns,nLines,0.0f);
    if(mat==0x0) return 0; 

    pthread_t m;
    pthread_t escravos[NT-1];
    pthread_create(&m, NULL, mestre, (void*)0);

    int i;
    for(i=0; i<NT-1; i++) pthread_create(&escravos[i], NULL, escravo, (void*)0);

    pthread_exit(NULL);

    printMatrixToFilePGM(mat,nColumns,nLines,"saida5.pgm");
    freeFloatMatrix(mat,nColumns,nLines);
    return 0;
}