DBus Study

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1, sudo apt-get install dbus-*

2, sudo apt-get install libdbus*

3, example

    #include <stdio.h>    #include <stdlib.h>    #include <dbus/dbus.h>    #include <unistd.h>         const int RES_SUCCESS = -1;    const int RES_FAILED  = 0;         int my_dbus_initialization(char const * _bus_name, DBusConnection ** _conn) {        DBusError err;             int ret;             dbus_error_init(&err);             *_conn = dbus_bus_get(DBUS_BUS_SESSION, &err);        if(dbus_error_is_set(&err)) {            printf("Connection Error\n");            dbus_error_free(&err);            return RES_FAILED;        }             ret = dbus_bus_request_name(*_conn, _bus_name, DBUS_NAME_FLAG_REPLACE_EXISTING, &err);        if(dbus_error_is_set(&err)){            printf("Requece name error \n");            dbus_error_free(&err);            return RES_FAILED;        }             if(DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER != ret) {            return RES_FAILED;        }             return RES_SUCCESS;    }         int my_dbus_send_sigal(DBusConnection * conn) {        dbus_uint32_t serial = 0;        DBusMessage* msg;        DBusMessageIter args;        char sigvalue[20] = "liyiwen";             msg = dbus_message_new_signal("/test/signal/Object",  // object name            "test.signal.Type",     // interface name            "Test");                // name of signal             if (NULL == msg) {            printf("Message Null");            return RES_FAILED;        }             dbus_message_iter_init_append(msg, &args);             printf("%s\n", sigvalue);        dbus_uint32_t my_age = 10;        if(!dbus_message_iter_append_basic(&args, DBUS_TYPE_UINT32, &my_age)) {            printf("Out of memory\n");            return RES_FAILED;        }             if(!dbus_connection_send(conn, msg, &serial)) {            printf("Out of memory");            return RES_FAILED;        }        dbus_connection_flush(conn);             dbus_message_unref(msg);             return RES_SUCCESS;         }         int main(int agrc, char** argv)    {        DBusConnection * conn;             printf("Start\n");        if (RES_FAILED == my_dbus_initialization("test.method.client", &conn)) {            exit(1);        }        my_dbus_send_sigal(conn);             while(1){sleep(10);}             return 0;    }

#include <stdio.h>#include <stdlib.h>#include <dbus/dbus.h>#include <unistd.h>const int RES_SUCCESS = -1;const int RES_FAILED  = 0;int my_dbus_initialization(char const * _bus_name, DBusConnection **_conn) {DBusError err;int ret;dbus_error_init(&err);*_conn = dbus_bus_get(DBUS_BUS_SESSION, &err);if(dbus_error_is_set(&err)) {    printf("Connection Error(%s) \n", err.message);    dbus_error_free(&err);    return RES_FAILED;}ret = dbus_bus_request_name(*_conn, _bus_name, DBUS_NAME_FLAG_REPLACE_EXISTING, &err);if(dbus_error_is_set(&err)){    printf("Requece name error(%s) \n", err.message);    dbus_error_free(&err);    return RES_FAILED;}if(DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER != ret) {    return RES_FAILED;}return RES_SUCCESS;}int main(int agrc, char** argv){DBusError err;DBusMessage* msg;DBusMessageIter args;dbus_error_init(&err);DBusConnection *conn;if (RES_FAILED == my_dbus_initialization("test.method.server", &conn)) {    exit(1);}dbus_bus_add_match(conn, "type='signal', interface='test.signal.Type'", &err);dbus_connection_flush(conn);if(dbus_error_is_set(&err)) {    printf("dbus_bus_add_match err (%s)", err.message);    return RES_FAILED;}while(1) {    dbus_connection_read_write(conn, 0);    msg = dbus_connection_pop_message(conn);    if(NULL == msg) {sleep(1);continue;    }    if(dbus_message_is_signal(msg, "test.signal.Type", "Test")) {if(!dbus_message_iter_init(msg, &args)) {    printf("dbus_message_iter_init error, msg has no arguments!\n");}else if (DBUS_TYPE_UINT32 != dbus_message_iter_get_arg_type(&args)){    printf("not a uint 32 type !\n");}else {    dbus_uint32_t my_age = 0;    dbus_message_iter_get_basic(&args, &my_age);    printf("Got signal with value %d\n", my_age);}    }    dbus_message_unref(msg);}return 0;}

4, error information fix

编译
----------------------------------------------------------
错误1:
$ gcc test.c
test.c:8:23: 错误： dbus/dbus.h：No such file or directory
......
$
错误提示，dbus库的头文件位置不正确(如果已经安装了dbus的话)
$ sudo updatedb
$ sudo locate dbus.h (查看dbus.h的所在位置)
/usr/local/include/dbus-1.0/dbus/dbus.h
/usr/include/dbus-1.0/dbus/dbus.h
看来dbus.h的存放位置的确不正确，这可能是由于dbus-1.0的安装位置有问题，没关系，调整一下dbus的头文件位置就可以了(调整方法如下):
root@zxl:/usr/include# ln -sf dbus-1.0/dbus

错误2:
$ gcc test.c
在包含自 test.c：8 的文件中:
/usr/include/dbus/dbus.h:29:33: 错误： dbus/dbus-arch-deps.h：No such file or directory
......

依然有头文件无法正确定位的问题，从错误提示来看，该文件应该在/usr/include/dbus/目录下，可是进入该目录查看竟然没有，那就在整个系统中查找该文件。
root@zxl:/usr/include/dbus# locate dbus-arch-deps.h
/usr/local/lib/dbus-1.0/include/dbus/dbus-arch-deps.h
/usr/lib/dbus-1.0/include/dbus/dbus-arch-deps.h
将该文件复制到/usr/include/dbus目录下

错误3:
$ gcc test.c
......
test.c:(.text+0xbb6): undefined reference to `dbus_message_iter_get_basic'
test.c:(.text+0xbd4): undefined reference to `dbus_message_unref'
collect2: ld 返回 1

需要连接动态库dbus
$ cd /usr/lib
$ ls *dbus*
libdbus-1.a libdbus-1.so.3 libdbus-glib-1.so
libdbus-1.la libdbus-1.so.3.2.0 libdbus-glib-1.so.2
libdbus-1.so libdbus-glib-1.a libdbus-glib-1.so.2.1.0

$ gcc test.c -l dbus-1 -o dbus

5, refers

http://hi.baidu.com/zengzhaonong/item/5143e33eb880abfedf222173

http://www.cnblogs.com/liyiwen/archive/2012/12/09/2810638.html

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