unix/linux进程详解——代码
#include <iostream>
#include <vector>
#include <cstdint>
#include <cstring>
#include <error.h>
#include <unistd.h>
using namespace std;
int main()
{
//system("ps aux &");//run on background
char *const ps_argv[]={"ps", "ax", 0};
//eg env
char *const ps_envp[]={"PATH=/bin:/usr/bin","TERM=console",0};
//possible exec
//execl("/bin/ps","ps","ax",0);//assume ps in the bin
//execlp("ps","ps","ax",0);//assume /bin is in the PATH
execle("/bin/ps","ps","ax",0,ps_envp);//pass own env
//execv("/bin/ps",ps_argv);
// execvp("ps",ps_argv);
// execve("/bin/ps",ps_argv,ps_envp);
// execlp("ps","ps","ax",0);
pid_t new_pid;
new_pid = fork();
new_pid = getpid();
cout << new_pid << endl;
switch (new_pid) {
case -1:
break;
case 0:
break;
default:
break;
}
cout << "errx" << endl;
return 0;
}
#include <iostream>
#include <vector>
#include <cstdint>
#include <cstring>
#include <error.h>
#include <unistd.h>
#include <sys/types.h>
using namespace std;
int main()
{
pid_t pid;
string message;
int n;
pid = fork();
//pid = getpid();
//cout << pid << endl;
switch (pid) {
case -1:
perror("fork failed");
exit(1);
case 0:
message = "this is the child";
n=5;
break;
default:
message = "this is the parent";
n=3;
break;
}
for(; n > 0;n--)
{
cout<<message<<endl;
sleep(1);
}
//cout << "errx" << endl;
return 0;
}
this is the parent
this is the child
this is the parent
this is the child
this is the parent
this is the child
$ this is the child
this is the child
#include <iostream>
#include <vector>
#include <cstdint>
#include <cstring>
#include <error.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
using namespace std;
int main()
{
pid_t pid;
string message;
int n;
int exit_code;
pid = fork();
//pid = getpid();
//cout << pid << endl;
switch (pid) {
case -1:
perror("fork failed");
exit(1);
case 0:
message = "this is the child";
n=5;
exit_code = 37;//casual set
break;
default:
message = "this is the parent";
exit_code = 0;
n=3;
break;
}
for(; n > 0;n--)
{
cout << message << ",which pid:" << getpid() << endl;
sleep(1);
}
if(pid != 0)
{
int stat_val;
pid_t child_pid;
child_pid = wait(&stat_val);
PRintf("child has finished: PID = %d\n",child_pid);
if(WIFEXITED(stat_val))
printf("child exited with code %d\n",WEXITSTATUS(stat_val));
else {
printf("child terminated abnormally\n");
}
}
//cout << "errx" << endl;
exit(exit_code);
}