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 #include <config.h>
   7
   8 #if defined (HAVE_UNISTD_H)
   9 #  include <unistd.h>
  10 #endif
  11
  12 #include <stdio.h>
  13
  14 #include "builtins.h"
  15 #include "shell.h"
  16 #include "bashgetopt.h"
  17
  18 /* A builtin `xxx' is normally implemented with an `xxx_builtin' function.
  19    If you're converting a command that uses the normal Unix argc/argv
  20    calling convention, use argv = make_builtin_argv (list, &argc) and call
  21    the original `main' something like `xxx_main'.  Look at cat.c for an
  22    example.
  23
  24    Builtins should use internal_getopt to parse options.  It is the same as
  25    getopt(3), but it takes a WORD_LIST *.  Look at print.c for an example
  26    of its use.
  27
  28    If the builtin takes no options, call no_options(list) before doing
  29    anything else.  If it returns a non-zero value, your builtin should
  30    immediately return EX_USAGE.  Look at logname.c for an example.
  31
  32    A builtin command returns EXECUTION_SUCCESS for success and
  33    EXECUTION_FAILURE to indicate failure. */
  34 hello_builtin (list)
  35      WORD_LIST *list;
  36 {
  37   printf("hello world\n");
  38   fflush (stdout);
  39   return (EXECUTION_SUCCESS);
  40 }
  41
  42 /* An array of strings forming the `long' documentation for a builtin xxx,
  43    which is printed by `help xxx'.  It must end with a NULL. */
  44 char *hello_doc[] = {
  45         "this is the long doc for the sample hello builtin",
  46         (char *)NULL
  47 };
  48
  49 /* The standard structure describing a builtin command.  bash keeps an array
  50    of these structures.  The flags must include BUILTIN_ENABLED so the
  51    builtin can be used. */
  52 struct builtin hello_struct = {
  53         "hello",                /* builtin name */
  54         hello_builtin,          /* function implementing the builtin */
  55         BUILTIN_ENABLED,        /* initial flags for builtin */
  56         hello_doc,              /* array of long documentation strings. */
  57         "hello",                /* usage synopsis; becomes short_doc */
  58         0                       /* reserved for internal use */
  59 };
  60