dbus发送与接收数据入门例子

1.dbus通信发送数据的代码例子：

（1）//dbus-send-hello.c

/*
cc $(pkg-config --cflags --libs dbus-glib-1) -o dbus-send-hello dbus-send-hello.c && ./dbus-send-hello
*/
int main (int argc, char *argv[])
{
DBusError dberr;
DBusConnection *dbconn;
DBusMessage *dbmsg;
char *text;
dbus_error_init (&dberr);
dbconn = dbus_bus_get (DBUS_BUS_SESSION, &dberr); //代表连接到会话总线，如果需要连接到
//系统总线，简单把DBUS_BUS_SESSION替换为DBUS_BUS_SYSTEM即可。但是有麻烦，因为
//系统总线对可以连接到它的用户有限制。可能需要提供一个.service文件指明能连接到某一个指定服务器的权限
if (dbus_error_is_set (&dberr)) {
fprintf (stderr, "getting session bus failed: %s\n", dberr.message);
dbus_error_free (&dberr);
return EXIT_FAILURE;
}
dbmsg = dbus_message_new_signal ("/com/wiley/test",
"com.wiley.test",
"TestSignal");
/* 函数原型是
DBusMessage* dbus_message_new_signal (const char *path,
const char *interface,
const char *name) */
if (dbmsg == NULL) {
fprintf (stderr, "Could not create a new signal\n");
return EXIT_FAILURE;
}
text = "Hello World";
dbus_message_append_args (dbmsg, DBUS_TYPE_STRING, &text, DBUS_TYPE_INVALID);
dbus_connection_send (dbconn, dbmsg, NULL);
printf ("Sending signal to D-Bus\n");
dbus_message_unref (dbmsg);
dbus_connection_unref (dbconn);
return EXIT_SUCCESS;
}

（2）重要代码片段

dbus_int32_t v_INT32 = 42;
const char *v_STRING = "Hello World";
dbus_message_append_args (message,
DBUS_TYPE_INT32, &v_INT32,
DBUS_TYPE_STRING, &v_STRING,
DBUS_TYPE_INVALID);
const dbus_int32_t array[] = { 1, 2, 3 };
const dbus_int32_t *v_ARRAY = array;
dbus_message_append_args (message,
DBUS_TYPE_ARRAY, DBUS_TYPE_INT32, &v_ARRAY, 3,
DBUS_TYPE_INVALID);
dbus_bool_t dbus_connection_send ( DBusConnection * connection,
DBusMessage * message,
dbus_uint32_t * serial
)
connection the connection.
message the message to write.
serial return location for message serial, or NULL if you don't care

2.dbus通信接收数据例子：

（1）//dbus-get-hello.c:

#include <dbus/dbus.h>
#include <stdlib.h>
#include <stdio.h>
/*
cc $(pkg-config --cflags --libs dbus-glib-1) -o dbus-get-hello dbus-get-hello.c && ./dbus-get-hello
*/
static DBusHandlerResult
filter_func (DBusConnection *connection,
DBusMessage *message,
void *user_data)
{
dbus_bool_t handled = FALSE;
char *signal_text = NULL;
if (dbus_message_is_signal (message, "com.wiley.test", "TestSignal")) {
DBusError dberr;
dbus_error_init (&dberr);
dbus_message_get_args (message, &dberr, DBUS_TYPE_STRING, &signal_text, DBUS_TYPE_INVALID);
if (dbus_error_is_set (&dberr)) {
fprintf (stderr, "Error getting message args: %s", dberr.message);
dbus_error_free (&dberr);
} else {
DBusConnection *dbconn = (DBusConnection*) user_data;
printf ("Received TestSignal with value of: '%s'\n", signal_text);
handled = TRUE;
}
}
return (handled ? DBUS_HANDLER_RESULT_HANDLED : DBUS_HANDLER_RESULT_NOT_YET_HANDLED);
}
int main (int argc, char *argv[])
{
DBusError dberr;
DBusConnection *dbconn;
dbus_error_init (&dberr);
dbconn = dbus_bus_get (DBUS_BUS_SESSION, &dberr);
if (dbus_error_is_set (&dberr)) {
fprintf (stderr, "getting session bus failed: %s\n", dberr.message);
dbus_error_free (&dberr);
return EXIT_FAILURE;
}
dbus_bus_request_name (dbconn, "com.wiley.test",
DBUS_NAME_FLAG_REPLACE_EXISTING, &dberr);
if (dbus_error_is_set (&dberr)) {
fprintf (stderr, "requesting name failed: %s\n", dberr.message);
dbus_error_free (&dberr);
return EXIT_FAILURE;
}
if (!dbus_connection_add_filter (dbconn, filter_func, NULL, NULL))
return EXIT_FAILURE;
dbus_bus_add_match (dbconn,
"type='signal',interface='com.wiley.test'",
&dberr);
if (dbus_error_is_set (&dberr)) {
fprintf (stderr, "Could not match: %s", dberr.message);
dbus_error_free (&dberr);
return EXIT_FAILURE;
}
while (dbus_connection_read_write_dispatch (dbconn, -1))
; /* empty loop body */
return EXIT_SUCCESS;
}

（2）//重要代码片段

dbus_bool_t dbus_connection_add_filter ( DBusConnection * connection,
DBusHandleMessageFunction function,
void * user_data,
DBusFreeFunction free_data_function
)
// connection the connection
// function function to handle messages
// user_data user data to pass to the function
// free_data_function function to use for freeing user data
//Adds a message filter.
if (!dbus_connection_add_filter (dbconn, filter_func, NULL, NULL))
return EXIT_FAILURE;
dbus_bus_add_match (dbconn,
"type='signal',interface='com.wiley.test'",
&dberr);
if (dbus_error_is_set (&dberr)) {
fprintf (stderr, "Could not match: %s", dberr.message);
dbus_error_free (&dberr);
return EXIT_FAILURE;
}
dbus_bool_t dbus_connection_read_write_dispatch ( DBusConnection * connection,
int timeout_milliseconds
)
//This function is intended for use with applications that don't want to //write a main loop and deal with DBusWatch and DBusTimeout.
// An example usage would be:
while (dbus_connection_read_write_dispatch (connection, -1))
; // empty loop body

参考链接：

http://dash1982.javaeye.com/?show_full=true

来源：CSDN

作者：neuharth

链接：https://blog.csdn.net/neuharth/article/details/7279126

标签

dbus

fprintf