我需要創建一個程序來創建n個進程並顯示信息。當每個過程結束時,我將打印它的PID和退出狀態。我做這件事的方式是,父程序等待創建下一個過程,直到當前過程結束。我需要它,以便它可以持續創建子進程,並在有一個進程結束時僅顯示出口信息,而不會阻止父進程繼續。我可以弄清楚在哪裏等待以確保這一點。以下是我的代碼:如何不用waitpid阻止父親
int main (int argc, char *argv[])
{
if (argc < 2)
{
printf("\n\nUsage: %s <enter a number (12 or less)>\n\n", argv[0]);
exit (-1);
}
else
{
int *processNum = (int *)malloc(sizeof(12));
int processNumTemp;
processNumTemp = atoi(argv[1]);
processNum = &processNumTemp;
if(*processNum > 12 || *processNum < 1)
{
printf("\n\nUsage: %s <enter a number (12 or lrss)>\n\n", argv[0]);
}
else
{
parentInfo(processNum);
createChildProcess(processNum);
}
}
return 0;
}
//Name: parentInfo
//Description: Displays information about the parent process
//Parameters: processNum - stores the number of child processes to create
// (entered at the command line).
//Return: none
void parentInfo(int *processNum)
{
printf("Parent process ID: %d\n", getppid());
printf("Number of processes to create: %d\n", *processNum);
}
//Name: createChildProcess
//Description: Creates n number of child processes.
// For each child process, it says its a child process and it
// displays its PID.
// After each child process closes, the parent displays info.
//Parameters: processNum - stores the number of child processes to create
// (entered at the command line).
//Return: none
void createChildProcess(int *processNum)
{
int i;
int childStatus;
pid_t childpid;
/*The for loop will create n number of processes based on the value of processNum.*/
for(i = 1; i <= *processNum; i++)
childpid = fork();
//Executes if fork didn't work
if(childpid < 0)
{
perror("fork");
exit(1);
}
//Executes if the fork worked
else if(childpid == 0)
{
int pid = getpid();
//Prints a message and the child processe's PID
printf("\nHello I am a child process.\n");
printf("My PID is %d. \n", getpid());
for(int x = 1; x <= pid; x ++);
exit(15);
}
}
//Executes after the child process has ended
//Checks the child process's exit status
waitpid(childpid, &childStatus, WUNTRACED);
printf("\nPID of the child process that was just created: %d.\n", childpid);
if(WIFEXITED(childStatus))
{
printf("PID %d exited normally. Exit number: %d\n", childpid, WEXITSTATUS(childStatus));
}
else if(WIFSTOPPED(childStatus))
{
printf("PID %d was stopped by %d\n", childpid, WSTOPSIG(childStatus));
}
else if(WIFSIGNALED(childStatus))
{
printf("PID %d exited due to signal %d\n.", childpid, WTERMSIG(childStatus));
}
else
{
perror("waitpid");
}
}
設置SIGCHLD的信號處理程序。在處理程序中調用'wait'。 – Duck