我为多个孩子创建管道。代码捕获来自键盘的信号，然后孩子应将消息及其结果发送给父亲。信号的处理工作正常，但我无法将结果发送给父亲。我在这里做错了吗？
父进程的代码是：
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <sys/types.h>
pid_t *childs; //array for storing childs pids
int number_of_childs;//variable for the number of childs
int exit_count=0;
int *fd;
/*Handler for the SIGINT signal*/
void control_handler(int sig)
{
if (sig==SIGINT){
int j,bytes;
char message[512];
/*Sending SIGUSR1*/
for (j=0;j<number_of_childs;j++)
{
kill(childs[j],SIGUSR1);
}
/*Reading from PIPES*/
for (j=0;j<number_of_childs;j++)
{
close(fd[(2*j)+1]);
bytes = read(fd[(2*j)], message, sizeof(message));
printf("Read from: %s\n",message);
close(fd[2*j]);
}
}
if (sig==SIGUSR2)
{
exit_count++;
}
}
main (int argc,char *argv[]){
int i,child_status;
char cast[512];
char cast2[512];
char cast3[512];
int pid;
number_of_childs=atoi(argv[1]);
signal(SIGINT,control_handler);
signal(SIGUSR2,control_handler);
/*Creating array for children pipes*/
fd=(int*)malloc((2*number_of_childs)*sizeof(int));
/*array that holds the pids for every child used in sending signals*/
childs=malloc(number_of_childs*sizeof (pid_t));
for (i=0;i<number_of_childs;i++){
pid=fork();
/*Create pipes to communicate with all children*/
if(pipe(fd+(2*i))==-1)
{
perror("pipe");exit(1);
}
/*Fathers code goes here*/
if(pid!=0)
{
printf("Parent process: PID= %d,PPID=%d, CPID=%d \n",getpid(),getppid(),pid);
childs[i]=pid; // Keep all your childs in an array
printf("Child:%d\n",childs[i]);
}
/*If you are a child*/
else
{
/*Change the code for the childs and set the time of execution*/
sprintf(cast,"%d",i+1); // make the time char
sprintf(cast2,"%d",(2*i)+1); //make the pipe char
sprintf(cast3,"%d",number_of_childs);
execl("./Child.out","",cast,cast2,cast3,NULL);
}
}
/*Father should never terminate*/
while (exit_count!=number_of_childs);
printf("Father pospastex!!\n");
}
孩子的代码是：
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <sys/types.h>
#include <time.h>
#include <string.h>
#define WRITE 0
#define READ 1
/*Global declerations*/
int alarmflag=0;
double result=0;
int count=0;
int global_pipe;
int *fd;
/*Handler for the alarm and SIGUSR1 signal*/
void signal_handler (int sig)
{
if(sig==SIGALRM)
{
printf("Im child with pid:%d im going to die my value is %lf \n",getpid(),result);
alarmflag=1;
}
if(sig==SIGUSR1)
{
count++;
char message[512];
if(count==1)
{
close(fd[global_pipe-1]);
sprintf(message,"%d,%lf",getpid(),result);
write(fd[global_pipe],message,strlen(message)+1);
close(fd[global_pipe]);
//printf("PID:%d report: %lf\n",getpid(),result);
}
if(count==2)
{
close(fd[global_pipe-1]);
sprintf(message,"%d,%lf",getpid(),result);
write(fd[global_pipe],message,strlen(message)+1);
close(fd[global_pipe]);
//printf("PID:%d report2 : %lf\n",getpid(),result);
//kill(getppid(),SIGUSR2);
//exit(0);
}
}
if(sig==SIGINT)
{
/*Do nothing*/
}
}
double p_calculation ()
{
int i=2;
result=3;
double prosimo=-1;
while(!alarmflag)
{
prosimo=prosimo*(-1);
result=result+(prosimo*(4/((double)i*((double)i+1)*((double)i+2))));
i=i+2;
}
}
main(int argc,char *argv[])
{
int pipe;
int size_fd;
size_fd=(atoi(argv[3]));
pipe=(atoi(argv[2]));
global_pipe=pipe;
fd=(int*)malloc(size_fd*sizeof(int));
/*handling signals*/
signal(SIGALRM,signal_handler);
signal(SIGUSR1,signal_handler);
signal(SIGINT,signal_handler);
/*Notify for execution time*/
printf("PID : %d with PPID : %d executing for %d seconds \n",getpid(),getppid(),atoi(argv[1]));
//printf("pipe:%d\n",pipe);
/*end this after the value passed as argument*/
alarm(atoi(argv[1]));
p_calculation();
/*Notify for finish*/
printf("Done!!!\n");
}