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What fork() Does

What fork() Does. for (int i = 0; i < 3; ++i) fork();. Each child process will be executing this same code:. for (int i = 0; i < 3; ++i) fork();. After fork() , when each child starts the data will be the same as its parent’s – i will not start at 0 for each child.

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What fork() Does

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  1. What fork()Does • for (int i = 0; i < 3; ++i) fork();

  2. Each child process will be executing this same code: • for (int i = 0; i < 3; ++i) fork();

  3. After fork(),when each child startsthe data will bethe same as its parent’s –i will not start at 0 for each child. • for (int i = 0; i < 3; ++i) fork();

  4. Start the process that has this code: • for (int i = 0; i < 3; ++i) fork();

  5. P1 • i contains: 0 • for (int i = 0; i < 3; ++i) fork();

  6. P1 • i contains: 0 • for (int i = 0; i < 3; ++i) fork();

  7. P1 P2 After fork() • i contains: 0 • i contains: 0 • for (int i = 0; i < 3; ++i) fork();

  8. P1 P2 Same Data In Child • i contains: 0 • i contains: 0 • for (int i = 0; i < 3; ++i) fork();

  9. P1 P2 After First Pass, BOTH incr i • i contains: 0 • i contains: 0 • for (int i = 0; i < 3; ++i) fork();

  10. P1 P2 • i contains: 1 • i contains: 1 • for (int i = 0; i < 3; ++i) fork();

  11. P1 P2 BOTH fork() • i contains: 1 • i contains: 1 • for (int i = 0; i < 3; ++i) fork();

  12. P1 P2 P3 P4 After fork() • i contains: 1 • i contains: 1 • i contains: 1 • i contains: 1 • for (int i = 0; i < 3; ++i) fork();

  13. Same Data In Each Child P1 P2 P3 P4 • i contains: 1 • i contains: 1 • i contains: 1 • i contains: 1 • for (int i = 0; i < 3; ++i) fork();

  14. After Second Pass, ALL incr i P1 P2 P3 P4 • i contains: 1 • i contains: 1 • i contains: 1 • i contains: 1 • for (int i = 0; i < 3; ++i) fork();

  15. P1 P2 P3 P4 • i contains: 2 • i contains: 2 • i contains: 2 • i contains: 2 • for (int i = 0; i < 3; ++i) fork();

  16. ALL fork() P1 P2 P3 P4 • i contains: 2 • i contains: 2 • i contains: 2 • i contains: 2 • for (int i = 0; i < 3; ++i) fork();

  17. P8 P1 P2 P3 P4 P5 P6 P7 After fork() • i contains: 2 • i contains: 2 • i contains: 2 • i contains: 2 • i contains: 2 • i contains: 2 • i contains: 2 • i contains: 2 • for (int i = 0; i < 3; ++i) fork();

  18. Same Data In Each Child P1 P2 P3 P4 P5 P6 P7 P8 • i contains: 2 • i contains: 2 • i contains: 2 • i contains: 2 • i contains: 2 • i contains: 2 • i contains: 2 • i contains: 2 • for (int i = 0; i < 3; ++i) fork();

  19. After Third Pass, ALL incr i P1 P2 P3 P4 P5 P6 P7 P8 • i contains: 2 • i contains: 2 • i contains: 2 • i contains: 2 • i contains: 2 • i contains: 2 • i contains: 2 • i contains: 2 • for (int i = 0; i < 3; ++i) fork();

  20. P1 P2 P3 P4 P5 P6 P7 P8 • i contains: 3 • i contains: 3 • i contains: 3 • i contains: 3 • i contains: 3 • i contains: 3 • i contains: 3 • i contains: 3 • for (int i = 0; i < 3; ++i) fork();

  21. P1 P2 P3 P4 P5 P6 P7 P8 the for statement is complete

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