尝试处理从父进程发送到所有子进程的 SIGUSR1 信号时,我遇到了问题。孩子的处理程序什么都不做。我检查了 kill 命令的结果,它返回 0 表示发送的消息正常。有人能帮忙吗?下面是子进程的代码。我使用 execl 来区分孩子的代码和父亲的代码。请注意,处理程序适用于警报调用
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <string.h>
/*Global declerations*/
int alarmflag=0;
double result=0;
int fd[2];
/*Handler for the alarm and SIGUSR1 signal*/
void signal_handler (int sig)
{
printf("******************");
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)
{
printf("gotit!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!\n");
}
}
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 fd[2];
/*handling signals*/
signal(SIGALRM,signal_handler);
signal(SIGUSR1,signal_handler);
/*Notify for execution time*/
printf("PID : %d with PPID : %d executing for %d seconds \n",getpid(),getppid(),atoi(argv[1]));
/*end this after the value passed as argument*/
alarm(atoi(argv[1]));
p_calculation();
/*Notify for finish*/
printf("Done!!!\n");
}
父亲的代码如下:
#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 count_controls=0;
/*Handler for the SIGINT signal*/
void control_handler(int sig)
{
int j;
for (j=0;j<number_of_childs;j++)
{
kill(childs[j],SIGUSR1);
}
}
main (int argc,char *argv[]){
int i,child_status;
int fd[2];
char cast[512];
int pid;
number_of_childs=atoi(argv[1]);
signal(SIGINT,control_handler);
childs=malloc(number_of_childs*sizeof (pid_t));
if(pipe(fd)==-1)
{
perror("pipe");exit(1);
}
for (i=0;i<number_of_childs;i++){
pid=fork();
/*Create pipes to communicate with all children*/
/*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);
execl("./Child.out","",cast,NULL);
}
}
/*Father should never terminate*/
while (1);
}