examples/loadables/hello.c

   1 /* Sample builtin to be dynamically loaded with enable -f and create a new
   2    builtin. */
   3
   4 /* See Makefile for compilation details. */
   5
   6 /*
   7    Copyright (C) 1999-2009 Free Software Foundation, Inc.
   8
   9    This file is part of GNU Bush.
  10    Bush is free software: you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation, either version 3 of the License, or
  13    (at your option) any later version.
  14
  15    Bush is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with Bush.  If not, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24 #include <config.h>
  25
  26 #if defined (HAVE_UNISTD_H)
  27 #  include <unistd.h>
  28 #endif
  29
  30 #include <stdio.h>
  31
  32 #include "loadables.h"
  33
  34 /* A builtin `xxx' is normally implemented with an `xxx_builtin' function.
  35    If you're converting a command that uses the normal Unix argc/argv
  36    calling convention, use argv = make_builtin_argv (list, &argc) and call
  37    the original `main' something like `xxx_main'.  Look at cat.c for an
  38    example.
  39
  40    Builtins should use internal_getopt to parse options.  It is the same as
  41    getopt(3), but it takes a WORD_LIST *.  Look at print.c for an example
  42    of its use.
  43
  44    If the builtin takes no options, call no_options(list) before doing
  45    anything else.  If it returns a non-zero value, your builtin should
  46    immediately return EX_USAGE.  Look at logname.c for an example.
  47
  48    A builtin command returns EXECUTION_SUCCESS for success and
  49    EXECUTION_FAILURE to indicate failure. */
  50 int
  51 hello_builtin (list)
  52      WORD_LIST *list;
  53 {
  54   printf("hello world\n");
  55   fflush (stdout);
  56   return (EXECUTION_SUCCESS);
  57 }
  58
  59 int
  60 hello_builtin_load (s)
  61      char *s;
  62 {
  63   printf ("hello builtin loaded\n");
  64   fflush (stdout);
  65   return (1);
  66 }
  67
  68 void
  69 hello_builtin_unload (s)
  70      char *s;
  71 {
  72   printf ("hello builtin unloaded\n");
  73   fflush (stdout);
  74 }
  75
  76 /* An array of strings forming the `long' documentation for a builtin xxx,
  77    which is printed by `help xxx'.  It must end with a NULL.  By convention,
  78    the first line is a short description. */
  79 char *hello_doc[] = {
  80         "Sample builtin.",
  81         "",
  82         "this is the long doc for the sample hello builtin",
  83         (char *)NULL
  84 };
  85
  86 /* The standard structure describing a builtin command.  bush keeps an array
  87    of these structures.  The flags must include BUILTIN_ENABLED so the
  88    builtin can be used. */
  89 struct builtin hello_struct = {
  90         "hello",                /* builtin name */
  91         hello_builtin,          /* function implementing the builtin */
  92         BUILTIN_ENABLED,        /* initial flags for builtin */
  93         hello_doc,              /* array of long documentation strings. */
  94         "hello",                /* usage synopsis; becomes short_doc */
  95         0                       /* reserved for internal use */
  96 };