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 int
  35 hello_builtin (list)
  36      WORD_LIST *list;
  37 {
  38   printf("hello world\n");
  39   fflush (stdout);
  40   return (EXECUTION_SUCCESS);
  41 }
  42
  43 /* An array of strings forming the `long' documentation for a builtin xxx,
  44    which is printed by `help xxx'.  It must end with a NULL.  By convention,
  45    the first line is a short description. */
  46 char *hello_doc[] = {
  47         "Sample builtin.",
  48         "",
  49         "this is the long doc for the sample hello builtin",
  50         (char *)NULL
  51 };
  52
  53 /* The standard structure describing a builtin command.  bash keeps an array
  54    of these structures.  The flags must include BUILTIN_ENABLED so the
  55    builtin can be used. */
  56 struct builtin hello_struct = {
  57         "hello",                /* builtin name */
  58         hello_builtin,          /* function implementing the builtin */
  59         BUILTIN_ENABLED,        /* initial flags for builtin */
  60         hello_doc,              /* array of long documentation strings. */
  61         "hello",                /* usage synopsis; becomes short_doc */
  62         0                       /* reserved for internal use */
  63 };
  64