man/vtable-example.c

   1 #include <errno.h>
   2 #include <stdbool.h>
   3 #include <stddef.h>
   4 #include <stdlib.h>
   5 #include <stdio.h>
   6 #include <systemd/sd-bus.h>
   7
   8 #define _cleanup_(f) __attribute__((cleanup(f)))
   9
  10 typedef struct object {
  11   char *name;
  12   uint32_t number;
  13 } object;
  14
  15 static int method(sd_bus_message *m, void *userdata, sd_bus_error *error) {
  16   printf("Got called with userdata=%p\n", userdata);
  17   return 1;
  18 }
  19
  20 static const sd_bus_vtable vtable[] = {
  21         SD_BUS_VTABLE_START(0),
  22         SD_BUS_METHOD(
  23             "Method1", "s", "s", method, 0),
  24         SD_BUS_METHOD_WITH_NAMES_OFFSET(
  25             "Method2",
  26             "so", SD_BUS_PARAM(string) SD_BUS_PARAM(path),
  27             "s", SD_BUS_PARAM(returnstring),
  28             method, offsetof(object, number),
  29             SD_BUS_VTABLE_DEPRECATED),
  30         SD_BUS_WRITABLE_PROPERTY(
  31             "AutomaticStringProperty", "s", NULL, NULL,
  32             offsetof(object, name),
  33             SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
  34         SD_BUS_WRITABLE_PROPERTY(
  35             "AutomaticIntegerProperty", "u", NULL, NULL,
  36             offsetof(object, number),
  37             SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
  38         SD_BUS_VTABLE_END
  39 };
  40
  41 #define check(x) ({                             \
  42   int r = x;                                    \
  43   errno = r < 0 ? -r : 0;                       \
  44   printf(#x ": %m\n");                          \
  45   if (r < 0)                                    \
  46     return EXIT_FAILURE;                        \
  47   })
  48
  49 int main(int argc, char **argv) {
  50   _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
  51
  52   sd_bus_default(&bus);
  53
  54   object object = { .number = 666 };
  55   check((object.name = strdup("name")) != NULL);
  56
  57   check(sd_bus_add_object_vtable(bus, NULL, "/object",
  58                                  "org.freedesktop.systemd.VtableExample",
  59                                  vtable,
  60                                  &object));
  61
  62   for (;;) {
  63     check(sd_bus_wait(bus, UINT64_MAX));
  64     check(sd_bus_process(bus, NULL));
  65   }
  66
  67   free(object.name);
  68
  69   return 0;
  70 }