forktest - forktest test fork This should work correctly...

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/* * forktest - test fork(). * * This should work correctly when fork is implemented. * * It should also continue to work after subsequent assignments, most * notably after implementing the virtual memory system. */ #include <unistd.h> #include <string.h> #include <stdlib.h> #include <stdio.h> #include <err.h> /* * This is used by all processes, to try to help make sure all * processes have a distinct address space. */ static volatile int mypid; /* * Helper function for fork that prints a warning on error. */ static int dofork(void) { int pid; pid = fork(); if (pid < 0) { warn("fork"); } return pid; } /* * Check to make sure each process has its own address space. Write * the pid into the data segment and read it back repeatedly, making * sure it's correct every time. */ static void check(void) { int i; mypid = getpid(); /* Make sure each fork has its own address space. */ for (i=0; i<800; i++) { volatile int seenpid; seenpid = mypid; if (seenpid != getpid()) { errx(1, "pid mismatch (%d, should be %d) " "- your vm is broken!", seenpid, getpid()); } }
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} /* * Wait for a child process.
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