System Call Error Handling

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• Unix function encountering errors typically returns -1 and set the global integer variable errno to indicate what went wrong.
  Example:

  if((pid = fork()) < 0){
  	fprintf(std, "fork error: %s\n", strerror(errno));
  	exit(0);
  }
  

• We can somehow simplify this by doing this:

  void unit_error(char *msg)
  {
  	fprintf(stderr, "%s: %s\n", msg, strerror(errno));
  	exit(0);
  }
  
  if((pid = fork()) < 0){
  	unix_error("fork error");
  }
  

• For this book we define error-handling wrappers, for a given function foo, we define a wrapper function Foo with identical args, this checks for error and terminates if there's any problem
• Example:

pid_t Fork(void){
	pid_t pid;
	if((pid = fork()) < 0)
		unix_error("Fork error");
	return pid;
}

Prev: Processes
TOC: Exceptional Control Flow
Next: Process Control