error.c

#include "apue.h"
#include <errno.h>		/* for definition of errno */
#include <stdarg.h>		/* ISO C variable aruments */

static void err_doit (int, int, const char *, va_list);

/*
 * Nonfatal error related to a system call.
 * Print a message and return.
 */
void
err_ret (const char *fmt, ...)
{
  va_list ap;

  va_start (ap, fmt);
  err_doit (1, errno, fmt, ap);
  va_end (ap);
}

/*
 * Fatal error related to a system call.
 * Print a message and terminate.
 */
void
err_sys (const char *fmt, ...)
{
  va_list ap;

  va_start (ap, fmt);
  err_doit (1, errno, fmt, ap);
  va_end (ap);
  exit (1);
}

/*
 * Nonfatal error unrelated to a system call.
 * Error code passed as explict parameter.
 * Print a message and return.
 */
void
err_cont (int error, const char *fmt, ...)
{
  va_list ap;

  va_start (ap, fmt);
  err_doit (1, error, fmt, ap);
  va_end (ap);
}

/*
 * Fatal error unrelated to a system call.
 * Error code passed as explict parameter.
 * Print a message and terminate.
 */
void
err_exit (int error, const char *fmt, ...)
{
  va_list ap;

  va_start (ap, fmt);
  err_doit (1, error, fmt, ap);
  va_end (ap);
  exit (1);
}

/*
 * Fatal error related to a system call.
 * Print a message, dump core, and terminate.
 */
void
err_dump (const char *fmt, ...)
{
  va_list ap;

  va_start (ap, fmt);
  err_doit (1, errno, fmt, ap);
  va_end (ap);
  abort ();			/* dump core and terminate */
  exit (1);			/* shouldn't get here */
}

/*
 * Nonfatal error unrelated to a system call.
 * Print a message and return.
 */
void
err_msg (const char *fmt, ...)
{
  va_list ap;

  va_start (ap, fmt);
  err_doit (0, 0, fmt, ap);
  va_end (ap);
}

/*
 * Fatal error unrelated to a system call.
 * Print a message and terminate.
 */
void
err_quit (const char *fmt, ...)
{
  va_list ap;

  va_start (ap, fmt);
  err_doit (0, 0, fmt, ap);
  va_end (ap);
  exit (1);
}

/*
 * Print a message and return to caller.
 * Caller specifies "errnoflag".
 */
static void
err_doit (int errnoflag, int error, const char *fmt, va_list ap)
{
  char buf[MAXLINE];

  vsnprintf (buf, MAXLINE - 1, fmt, ap);
  if (errnoflag)
    snprintf (buf + strlen (buf), MAXLINE - strlen (buf) - 1, ": %s",
	      strerror (error));
  strcat (buf, "\n");
  fflush (stdout);		/* in case stdout and stderr are the same */
  fputs (buf, stderr);
  fflush (NULL);		/* flushes all stdio output streams */
}