I would like to ask how I can run another program in a progaram already running.


That is a program is used to check something and when something occurs,
this program will stop and another program will start~~~


Thanks again~~

What language?

In C and C++, you can use the 'exec' family of functions (check out the 'exec' man page); in bash and other scripting languages you can usually just enclose a command in "`" (reverse single quotes) to execute it.

In C/C++ I use

system("run your script here or just execute directly"); // like commandline

the system call takes care of fork, exec etc

so what header file I have to include.

system("./test.o");


where test.o is the file to be run, is the command correct?

Thanks kalleanka and wapcaplet

I have checked that the command
system("./test.o");
works well when I want to upgrade the file but not make a connection to other pc.

besides I have tried using execl to update file too ..but can't make connection..

Are there any special technique in using them?

From the man page, it doesn't mention any sample code, it is really hard for me to get the correct thing I want.

Could anyone guide me (or show me the exact code)

thanks again and agian~~

I'm not sure what you mean by "upgrading the file" or making a connection to another PC. Could you explain a little more?

Suppose there are 3 PCs. message sent from pc 1 to pc 3 through pc 2,

pc 1 is running a server.o program to wait for connection from another pc.

when packet sent from pc 1 to pc 3 through pc 2, pc 2 will use a iptables command (-j QUEUE)to pass the packet to the queue and then a userspace program which starts running at the beginning will try to make connection to pc 1.
( I have add the command execl("client.o","",(char *) 0); at the userspace program at pc 2, but it fails to make connection to pc 1.)
(But it works if I just add the command execl("add.o","",(char *) 0); )

add.o is just a program for adding iptables command
client.o is a program for making connection to pc 1

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
I want to ask if I can get the message sent from pc 1 to pc 3 at pc 2 even the connection is made only between pc 1 and pc 3.

Actually, I want to do this .....

I have no idea at all~~~

So, I try to pass the packet to the queue at pc 2, run a userspace program--make connection to pc 1 and ask pc 1 to send the message to pc 2~~~

Thanks wapcaplet ~~

Could you show me the function or anything useful to solve my problem....

I have tried many many .....methods before

Thanks a lot~~~