vfork():

 The vfork() function is the same as fork() except that it does not make a copy of the address space. The memory is shared reducing the overhead of spawning a new process with a unique copy of all the memory. This is typically used when using fork() to exec() a process and terminate. The vfork() function also executes the child process first and resumes the parent process when the child terminates.

01 #include <iostream>

02	#include <string>

03

04	// Required by for routine

05	#include <sys/types.h>

06	#include <unistd.h>

07

08	using namespace std;

09

10

11	int globalVariable = 2;

12

13

main()

14

{

15	string sIdentifier;

16	int    iStackVariable = 20;

17

18	pid_t pID = vfork();

19	if (pID == 0)                // child

20

{

21	// Code only executed by child process

22

23	sIdentifier = "Child Process: ";

24	globalVariable++;

25	iStackVariable++;

26	cout << sIdentifier;

27	cout << " Global variable: " << globalVariable;

28	cout << " Stack variable: "  << iStackVariable << endl;

29

_exit(0);

30

}

31	else if (pID < 0)            // failed to fork

32

{

33	cerr << "Failed to fork" << endl;

34

exit(1);

35	// Throw exception

36

}

37	else                                   // parent

38

{

39	// Code only executed by parent process

40

41	sIdentifier = "Parent Process:";

42

}

43

44	// executed only by parent

45

46	cout << sIdentifier;

47	cout << " Global variable: " << globalVariable;

48	cout << " Stack variable: "  << iStackVariable << endl;

49

exit(0);

50

}