1 /* $OpenBSD: help.c,v 1.5 2003/04/14 14:33:57 millert Exp $ */
2
3 /*
4 * Copyright (c) 1984,1985,1989,1994,1995 Mark Nudelman
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice in the documentation and/or other materials provided with
14 * the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY
17 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
22 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
23 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
24 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
25 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
26 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29
30 /*
31 * Display some help.
32 * Just invoke another "less" to display the help file.
33 *
34 * {{ This makes this function very simple, and makes changing the
35 * help file very easy, but it may present difficulties on
36 * (non-Unix) systems which do not supply the "system()" function. }}
37 */
38
39 #include "less.h"
40
41 extern char *progname;
42
43 public void
help(nomsg)44 help(nomsg)
45 int nomsg;
46 {
47 #ifdef HELPFILE
48 char *helpfile;
49 char *cmd;
50 size_t len;
51
52 helpfile = find_helpfile();
53 if (helpfile == NULL)
54 {
55 error("Cannot find help file", NULL_PARG);
56 return;
57 }
58 #if !HAVE_SYSTEM
59 /*
60 * Just examine the help file.
61 */
62 (void) edit(helpfile);
63 #else
64 /*
65 * Use lsystem() to invoke a new instance of less
66 * to view the help file.
67 */
68 #if MSDOS_COMPILER
69 putenv("LESS=-m -H -+E -+s -PmHELP -- ?eEND -- Press g to see it again:Press RETURN for more., or q when done");
70 len = strlen(helpfile) + strlen(progname) + 3;
71 cmd = (char *) ecalloc(len, sizeof(char));
72 snprintf(cmd, len, "-%s %s", progname, helpfile);
73 #else
74 len = strlen(helpfile) + strlen(progname) + 150;
75 cmd = (char *) ecalloc(len, sizeof(char));
76 #if OS2
77 snprintf(cmd, len,
78 "-%s -m -H -+E -+s \"-PmHELP -- ?eEND -- Press g to see it again:Press RETURN for more., or q when done \" %s",
79 progname, helpfile);
80 #else
81 snprintf(cmd, len,
82 "-%s -m -H -+E -+s '-PmHELP -- ?eEND -- Press g to see it again:Press RETURN for more., or q when done ' %s",
83 progname, helpfile);
84 #endif
85 #endif
86 free(helpfile);
87 lsystem(cmd, (char*)NULL);
88 if (!nomsg)
89 error("End of help", NULL_PARG);
90 free(cmd);
91 #endif
92 #else
93 error("Cannot find help file", NULL_PARG);
94 #endif
95 }
96