usage.c

本程序集是Allen I. Holub所写的《Compiler Design in C》一书的附随软件

/*
 * 68K/386 32-bit C compiler.
 *
 * copyright (c) 1997, David Lindauer
 * 
 * This compiler is intended for educational use.  It may not be used
 * for profit without the express written consent of the author.
 *
 * It may be freely redistributed, as long as this notice remains intact
 * and either the original sources or derived sources 
 * are distributed along with any executables derived from the originals.
 *
 * The author is not responsible for any damages that may arise from use
 * of this software, either idirect or consequential.
 *
 * v1.35 March 1997
 * David Lindauer, [e-mail]
 *
 * Credits to Mathew Brandt for original K&R C compiler
 *
 */
/*
 * Display usage information and exit.
 */
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdarg.h>
#include "cmdline.h"
/*
 * Main program must define the usage text
 */
extern char *usage_text;

/* Program banner */
void banner( char *fmt, ... )
{
  va_list argptr;

  putc('\n', stdout);

  va_start( argptr, fmt);
  vprintf( fmt, argptr);
  va_end(argptr);

  putc('\n', stdout);
  putc('\n', stdout);
}

/* Print usage info */
void usage( char *prog_name)
{
  char *short_name;
  char *extension;

  short_name = strrchr(prog_name, '\\' );
  if (short_name == NULL)
    short_name = strrchr( prog_name, '/' );
  if (short_name == NULL)
    short_name = strrchr( prog_name, ':' );
  if (short_name)
    short_name++;
  else
    short_name = prog_name;

  extension = strrchr( short_name, '.');
  if (extension != NULL)
    *extension = '\0';
  printf("\nUsage: %s %s\n", short_name, usage_text);
  exit( 1 );
}