Session 4061 8 (2/8)
Today
Error Handling in C Fork, Exec, Wait
Admin
Homework 2
1
Sys Call Errors (Robbins 2.4)
Concepts
Sys calls return -1 on error Restarting sys calls
C Features
perror(const char *s) errno char *strerror(int errnum) fprintf(stderr, ...)
fork()
What are the return values of fork for parent and child? What is copy-on-write, and how does it improve the performance of fork?
Getting Info About A Process
calls:
getpid(), getppid() getgid(), getuid(), getegid(), geteuid()
2
wait()
calls: wait(..), waitpid(..) is What blocking? How do you check the status of a child process without blocking? zombie process orphan process Macros for checking return status (e.g. WIFEXITED, WEXITSTATUS)
exec()
calls: many variants! See Robbins pg. 7879 What happens to a process when exec is called?
exit()
calls: exit(..), _exit(..) return fro...