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Fork and exec to run external needed app

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Join Date: May 2005

Posts: 18

Reputation: Mr. is an unknown quantity at this point

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Mr.

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Fork and exec to run external needed app

May 15th, 2005

Hello,

I have a small app that uses pipes to do some basic client / server communication, just for testing purposes.

Well, when the server is run before the client, it works fine. However, if the client is run before the server, there are problems. To solve this I wanted to start the server from inside the client, if the client sees that there's no server.

This can possibly be done using fork and exec (exec to run the server binary file, replacing the child process's image.

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
if ( server_pipe == -1 ) {
   if ( fork == 0 ) {
      /* run exec function to start the server */
   }
}
if ( server_pipe == -1 ) {
   if ( fork == 0 ) {
      /* run exec function to start the server */
   }
}

I have been trying to do so, without sucess. I think that scheduling issues may affect the ability to run one from the other - because there are loops both in the server and in the client, that wait for input.

Is this possible or this there another better way to do it?

Thanks for your help.

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Join Date: May 2005

Posts: 232

Reputation: Dogtree is an unknown quantity at this point

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Dogtree

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Re: Fork and exec to run external needed app

May 15th, 2005

I would think that if there's no server, that's a fatal error for the client. Since this is for testing purposes, why bother with an elaborate workaround when you can simply make sure that you run the server first?

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Join Date: May 2005

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Mr.

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Re: Fork and exec to run external needed app

May 15th, 2005

•

Originally Posted by Dogtree

I would think that if there's no server, that's a fatal error for the client. Since this is for testing purposes, why bother with an elaborate workaround when you can simply make sure that you run the server first?

Testing and learning purposes (the teacher asked it ).

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Join Date: May 2005

Posts: 18

Reputation: Mr. is an unknown quantity at this point

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Mr.

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Re: Fork and exec to run external needed app

May 15th, 2005

After investigating... (ps -xua)

* the server does get started (appears on process list using ps -xua)
* that processe's state is S (sleeping)

Any ideas?

Thanks.