我正在寻找一个C代码来测量它在两个简单应用程序之间发送数据所用的时间，而不使用任何GLIB绑定，我在许多帖子中看到，“AA>有一个例子，但是链接现在不存在。
我的代码发送时没有给出任何错误，但是接收应用程序没有收到任何东西，还附加了service.conf文件。从其他网站获得此代码：
////////////////////////////Sender Code
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <signal.h>
#include <dbus/dbus.h>
#define false 0
#define true 1
#define bool char
#define DERR_SHOW_CLEAN(error) \
if (dbus_error_is_set(&(error))) \
{ \
printf("error [%s:%d] %s\n %s\n", \
__FILE__, __LINE__, error.name, error.message); \
dbus_error_free(&(error)); \
}
int main() {
dbus_bool_t rc;
DBusError error;
DBusConnection* conn;
int ret;
char* sigvalue = "Test";
// initialise the errors
dbus_error_init(&error); //TODO
conn = dbus_connection_open("unix:path=/dev/shmem/dbus_service_socket", &error);
DERR_SHOW_CLEAN(error);
dbus_uint32_t serial = 0; // unique number to associate replies with requests
DBusMessage* msg;
DBusMessageIter args;
rc = dbus_bus_register(conn, &error);
DERR_SHOW_CLEAN(error);
// create a signal and check for errors
msg = dbus_message_new_signal("/org/freedesktop/DBus", // object name of the signal
"org.freedesktop.DBus", // interface name of the signal
"Test"); // name of the signal
if (NULL == msg)
{
fprintf(stderr, "Message Null\n");
}
// append arguments onto signal
dbus_message_iter_init_append(msg, &args);
if (!dbus_message_iter_append_basic(&args, DBUS_TYPE_STRING, &sigvalue)) {
fprintf(stderr, "Out Of Memory!\n");
}
while(1)
{
// send the message and flush the connection
if (!dbus_connection_send(conn, msg, &serial)) {
fprintf(stderr, "Out Of Memory!\n");
break;
}
else
{
sleep(5);
}
}
dbus_connection_flush(conn);
// free the message
dbus_message_unref(msg);
return 0;
}
////////////////////////////Receiver Code
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <dbus/dbus.h>
#define false 0
#define true 1
#define bool char
#define DERR_SHOW_CLEAN(error) \
if (dbus_error_is_set(&(error))) \
{ \
printf("error [%s:%d] %s\n %s\n", \
__FILE__, __LINE__, error.name, error.message); \
dbus_error_free(&(error)); \
}
int main()
{
DBusError err;
DBusConnection* conn;
DBusMessage* msg;
DBusMessageIter args;
int ret;
char* sigvalue;
dbus_bool_t rc;
// initialise the errors
dbus_error_init(&err); //TODO
conn = dbus_connection_open("unix:path=/dev/shmem/dbus_service_socket", &err);
DERR_SHOW_CLEAN(err);
rc = dbus_bus_register(conn, &err);
DERR_SHOW_CLEAN(err);
while (true) {
// non blocking read of the next available message
dbus_connection_read_write(conn, 0);
msg = dbus_connection_pop_message(conn);
printf("Got Si3\n");
// loop again if we haven't read a message
if (NULL == msg) {
sleep(5);
continue;
}
// check if the message is a signal from the correct interface
// and with the correct name
if (dbus_message_is_signal(msg, "org.freedesktop.DBus", "Test")) {
// read the parameters
printf("Got Si4\n");
if (!dbus_message_iter_init(msg, &args))
fprintf(stderr, "Message has no arguments!\n");
else if (DBUS_TYPE_STRING != dbus_message_iter_get_arg_type(&args))
fprintf(stderr, "Argument is not string!\n");
else {
dbus_message_iter_get_basic(&args, &sigvalue);
printf("Got Signal with value %s\n", sigvalue);
}
}
else
{
printf("Got Signal with type %s\n", dbus_message_get_sender(msg));
}
// free the message
dbus_message_unref(msg);
}
}
/////service.conf file contents which is used while dbus-daemon starts
<!-- This configuration file controls the systemwide message bus.
Add a system-local.conf and edit that rather than changing this
file directly. -->
<!-- Note that there are any number of ways you can hose yourself
security-wise by screwing up this file; in particular, you
probably don't want to listen on any more addresses, add any more
auth mechanisms, run as a different user, etc. -->
<!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-Bus Bus Configuration 1.0//EN"
"http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
<busconfig>
<!-- Our well-known bus type, do not change this -->
<type>system</type>
<!-- Run as special user -->
<user>root</user>
<!-- Fork into daemon mode -->
<fork/>
<!-- Write a pid file -->
<pidfile>/dev/shmem/dbus_service.pid</pidfile>
<!-- Enable logging to syslog -->
<syslog/>
<!-- allow everyone -->
<allow_anonymous />
<!-- Only allow socket-credentials-based authentication -->
<!-- <auth>EXTERNAL</auth>-->
<!-- Only listen on a local socket. (abstract=/path/to/socket
means use abstract namespace, don't really create filesystem
file; only Linux supports this. Use path=/whatever on other
systems.) -->
<listen>unix:path=/dev/shmem/dbus_service_socket</listen>
<policy context="default">
<!-- All users can connect to system bus -->
<allow user="*"/>
<allow group="*"/>
<allow own="*"/>
<!-- Signals and reply messages (method returns, errors) are allowed
by default -->
<allow send_type="signal"/>
<allow send_type="method_call" log="true"/>
<allow send_requested_reply="true" send_type="method_return"/>
<allow send_requested_reply="true" send_type="error"/>
<!-- All messages may be received by default -->
<allow receive_type="method_call"/>
<allow receive_type="method_return"/>
<allow receive_type="error"/>
<allow receive_type="signal"/>
<allow receive_interface="org.freedesktop.DBus.Introspectable"/>
<allow send_destination="*"/>
<allow receive_sender="*" />
<allow receive_path="/org/freedesktop/DBus"/>
<!-- Allow anyone to talk to the message bus -->
<allow send_destination="org.freedesktop.DBus"/>
</policy>
<!-- Config files are placed here that among other things, punch
holes in the above policy for specific services. -->
<includedir>service.d</includedir>
</busconfig>
最佳答案
在接收主函数中进入while循环之前调用dbus_bus_add_match，它可以工作
参考示例：athttps://github.com/Jeshwanth/dbus-1/blob/master/dbus-1/dbus-example.c
关于c - DBus:使用直接的dbus API测量数据交换的时间，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/27340237/