请问如何在exec时指定新进程在后台运行？

jxy02

多谢！

sagaeon

没用过，加个&行不？

jxy02

加“&”也不行

sagaeon

运行有什么现象?

jxy02

和不加"&"的效果一样

sagaeon

做成守护进程。

jxy02

有道理，谢谢！

mozilla

用fork2可以脱离父进程,也算是后台进程吧

chriszc

请问exec的具体用法是什么啊？
现在急需要知道！

mozilla

man 2 exec

flyaway

[code:1]
        #include <stdio.h>
        #include <stdlib.h>
        #include <sys/types.h>
        #include <unistd.h>
        /* Spawn a child process running a new program. PROGRAM is the name
        of the program to run; the path will be searched for this program.
        ARG_LIST is a NULL-terminated list of character strings to be
        passed as the program’s argument list. Returns the process ID of
        the spawned process. */
        int spawn (char* program, char** arg_list)
        {
                pid_t child_pid;
                /* Duplicate this process. */
                child_pid = fork ();
                if (child_pid != 0)
                /* This is the parent process. */
                return child_pid;
                else
                {
                        /* Now execute PROGRAM, searching for it in the path. */
                        execvp (program, arg_list);
                        /* The execvp function returns only if an error occurs. */
                        fprintf (stderr, “an error occurred in execvp\n”);
                        abort ();
                }
        }
        int main ()
        {
                /* The argument list to pass to the “ls” command. */
                char* arg_list[] =
                {
                        “ls”, /* argv[0], the name of the program. */
                        “-l”,
                        “/”,
                        NULL /* The argument list must end with a NULL. */
                };
                /* Spawn a child process running the “ls” command. Ignore the
                returned child process ID. */
                spawn (“ls”, arg_list);
                printf (“done with main program\n”);
                return 0;
        }

[/code:1][/code]

flyaway

[code:1]
        #include <stdio.h>
        #include <stdlib.h>
        #include <sys/types.h>
        #include <unistd.h>
        /* Spawn a child process running a new program. PROGRAM is the name
        of the program to run; the path will be searched for this program.
        ARG_LIST is a NULL-terminated list of character strings to be
        passed as the program’s argument list. Returns the process ID of
        the spawned process. */
        int spawn (char* program, char** arg_list)
        {
                pid_t child_pid;
                /* Duplicate this process. */
                child_pid = fork ();
                if (child_pid != 0)
                /* This is the parent process. */
                return child_pid;
                else
                {
                        /* Now execute PROGRAM, searching for it in the path. */
                        execvp (program, arg_list);
                        /* The execvp function returns only if an error occurs. */
                        fprintf (stderr, “an error occurred in execvp\n”);
                        abort ();
                }
        }
        int main ()
        {
                /* The argument list to pass to the “ls” command. */
                char* arg_list[] =
                {
                        “ls”, /* argv[0], the name of the program. */
                        “-l”,
                        “/”,
                        NULL /* The argument list must end with a NULL. */
                };
                /* Spawn a child process running the “ls” command. Ignore the
                returned child process ID. */
                spawn (“ls”, arg_list);
                printf (“done with main program\n”);
                return 0;
        }

[/code:1][/code]