[英]How to terminate a c program after 20 seconds
我試圖在 20 秒后終止具有多種功能的 c 程序(殺死所有子進程和父進程,關閉文件)。 我試過鬧鍾(),定時器(),時鍾()。 當我們只有一個 main 和一個處理程序 function 時,它可以工作。 即使我將變量保持在全局范圍內,clock() 也會在每個 function 中從 0 重新開始。
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <time.h>
#include <stdlib.h>
#include <dirent.h>
#include <stdio.h>
#include <string.h>
#include <getopt.h>
#include<stdbool.h>
#include <ctype.h>
#include<sys/wait.h>
#include<signal.h>
#include <sys/mman.h>
#include<sys/time.h>
#define INTERVAL 2
int t=0;
void display_message()
{
printf("In the handler");
//kill(0,SIGKILL);
t=1;
}
void calling2()
{
signal(SIGALRM, display_message);
sleep(3);
}
void calling()
{
signal(SIGALRM, display_message);
alarm(2);
int i;
for(i=0;i<3;i++)
{
//printf("\nStarting fork for loop i=%d \n",i);
pid_t pID = fork();
if (pID == 0) // child
{
calling2();
if(t==1)
{
printf("we have exceeded 2 seconds killing the process");
kill(0,SIGKILL);
exit(0);
}
exit(0);
kill(pID,SIGKILL);
}
else if(pID>0)
{
// printf("\nhello from the father");
if(t==1)
{
printf("killing the process");
kill(0,SIGKILL);
exit(0);
}
printf("\nhello from the father");
}
}
}
如您所見,我嘗試從不同的函數調用信號,以便它可以捕獲信號並且處理程序可以執行,但處理程序永遠不會執行。
編輯:再試一次
# include <unistd.h>
# include <sys/types.h>
# include <sys/stat.h>
# include <time.h>
# include <stdlib.h>
# include <dirent.h>
# include <stdio.h>
# include <string.h>
# include <getopt.h>
# include<stdbool.h>
# include <ctype.h>
# include<sys/wait.h>
# include<signal.h>
# include <sys/mman.h>
# include<sys/time.h>
# define INTERVAL 2
int t=0;
void display_message()
{
kill(0,SIGKILL);
t=1;
}
void calling2()
{
sleep(3);
}
void calling()
{
signal(SIGALRM, display_message);
int i;
for(i=0;i<3;i++)
{
pid_t pID = fork();
if (pID == 0) // child
{
calling2();
if(t==1)
{
printf("killing the process");
kill(0,SIGKILL);
exit(0);
}
exit(0);
}
else if(pID>0)
{
if(t==1)
{
printf("killing the process");
kill(0,SIGKILL);
exit(0);
}
printf("\nhello from the father");
}
}
}
int main()
{
signal(SIGALRM, display_message);
alarm(2);
calling();
}
O/P:
hello from the father
hello from the father
hello from the father
hello from the father
hello from the father
hello from the father
error: Failed with return code 22
主要問題是您的主線程在處理警報信號之前完成。 您必須至少讓它存活,直到發出警報信號。 此外,正如 Jonathan Leffler 所建議的那樣,良好的縮進/間距確實很有幫助。
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <time.h>
#include <stdlib.h>
#include <dirent.h>
#include <stdio.h>
#include <string.h>
#include <getopt.h>
#include <stdbool.h>
#include <ctype.h>
#include <sys/wait.h>
#include <signal.h>
#include <sys/mman.h>
#include <sys/time.h>
#define INTERVAL 2
int t=0;
void display_message()
{
kill(0,SIGKILL);
t=1;
}
void calling2()
{
sleep(3);
}
void calling()
{
signal(SIGALRM, display_message);
int i;
for(i=0;i<3;i++)
{
pid_t pID = fork();
if (pID == 0) // child
{
calling2();
if(t==1)
{
printf("killing the process");
kill(0,SIGKILL);
exit(0);
}
exit(0);
}
else if(pID>0)
{
if(t==1)
{
printf("killing the process");
kill(0,SIGKILL);
exit(0);
}
printf("\nhello from the father");
}
}
}
int main()
{
signal(SIGALRM, display_message);
alarm(2);
calling();
// wait until alarm callback before terminating main thread
sleep(100);
}
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