| 12.1 | Run the program in Figure 12.17 on a Linux system, but redirect the output into a file. Explain the results. |
| 12.2 | Implement putenv_r, a reentrant version of putenv. Make sure that your implementation is async-signal safe as well as thread-safe. |
| 12.3 | Can you make the program in Figure 12.13 async-signal safe by blocking signals at the beginning of the function and restoring the previous signal mask before returning? Explain. |
| 12.4 | Write a program to exercise the version of getenv from Figure 12.13. Compile and run the program on FreeBSD. What happens? Explain. |
| 12.5 | Given that you can create multiple threads to perform different tasks within a program, explain why you might still need to use fork. |
| 12.6 | Reimplement the program in Figure 10.29 to make it thread-safe without using nanosleep. |
| 12.7 | After calling fork, could we safely reinitialize a condition variable in the child process by first destroying the condition variable with pthread_cond_destroy and then initializing it with pthread_cond_init? |
