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hbak
hbak

Reputation: 1323

how to know parent or child process in vfork function

I wonder if we use vfork, how do we know the child process or parent process since the resources are shared?

To be more specific, assume the following code:

int main()
{
   int pid = vfork();
   if(pid == 0)
   {
      // code for child
   }
   else 
   {
      // code for parent
   }
   return 0;  
}

In the code above, if the resources are shared, then the pid variable will have a unique value, so is this code valid? Since I have seen examples do things as the above code.

Upvotes: 1

Views: 738

Answers (3)

LearningC
LearningC

Reputation: 3162

vfork() suspends the parent until the child either calls exec*() or _exit().

using vfork() in this format as we use fork() results in program run in infinite loop. it doesn't end.
read this discussion to get better idea about using vfork().

Upvotes: 2

Lee Duhem
Lee Duhem

Reputation: 15121

is this code is valid ?

Yes. vfork() still will make a copy of parent process (conceptually), and as normal fork(), in the child process it will return 0, in the parent process the pid of that child process.

Upvotes: 0

prmottajr
prmottajr

Reputation: 1824

In vfork the parent will wait the child to finish, so there is no need to differentiate.

Upvotes: 0

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