DLT（Diagnostic Log and Trace）嵌入式系统程序运行记录

最新推荐文章于 2025-06-12 09:05:31 发布

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最新推荐文章于 2025-06-12 09:05:31 发布 · 2w 阅读

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#DLT #log #DeBug

DLT的使用有属于Application范畴与Context范畴。在使用DLT时，需要包含以下头文件：

#include <dlt/dlt.h>

同时需要link相应的dlt库文件。

Context范畴需要使用以下statement去申明及注册：

DLT_DECLARE_CONTEXT(BCcontext); // declare the context name.

DLT_REGISTER_CONTEXT(BCcontext,"BCCT","DLT BC Context"); // register the Context id.

DLT_IMPORT_CONTEXT(BCcontext); // import DLT Context in other source file.

DLT_UNREGISTER_CONTEXT(BCcontext);   // DLT Context un-registration

Application范畴需要使用以下statement去注册：

DLT_REGISTER_APP("BC","DLT BC DBUS Wrapper"); // register the Application id.
DLT_UNREGISTER_APP(); // DLT Application un-registration

//Set daemon log limit and trace status. Anything above this log level will not be printed.

DLT_SET_APPLICATION_LL_TS_LIMIT(DLT_LOG_DEBUG, DLT_TRACE_STATUS_DEFAULT);

DLT log 有以下几种格式

DLT_LOG(BCcontext,DLT_LOG_INFO,DLT_STRING("output normal information directly.")); 
DLT_LOG(BCcontext,DLT_LOG_WARN,DLT_STRING("output warning information directly."));  
DLT_LOG(BCcontext,DLT_LOG_ERROR,DLT_STRING("output error information directly.")); 

DLT_LOG(BCcontext,DLT_LOG_INFO,DLT_STRING("RadioMsg_Signal_Coverage_Area_Handler"),                                                 
                           DLT_STRING("default type data"),DLT_UINT(default value),
                           DLT_STRING("one byte"),DLT_UINT8(char),
                           DLT_STRING("two byte"),DLT_UINT16(short),
                           DLT_STRING("four byte"),DLT_UINT32(int));

上位机可以使用DLT-viewer软件通过网络SSH协议连接到目标板上去查看系统的运行情况。

DLT library

To use DLT from an application, the application has to link again the DLT library. When the DLT daemon is installed on the system , there will a shared library with the name libdlt.so which provides the interface for applications to get a connection to the DLT daemon. The library path and include path must be set in the build environment prior to building a program using the shared dlt library. By default, the include file “dlt.h” is located in a directory called “dlt/” within the standard include directory.

Using DLT with cmake
To use DLT with cmake, the following lines are the important ones:

pkg_check_modules(DLT REQUIRED automotive-dlt)

to INCLUDE_DIRECTORIES, add

${DLT_INCLUDE_DIRS}

and to TARGET_LINK_LIBRARIES:

${DLT_LIBRARIES}

Logging instruction
Include the dlt header file:

#include <dlt/dlt.h>

Create logging context (place it beneath the define section):

DLT_DECLARE_CONTEXT(myContext);

int main(int argc, const char\* argv\[\])
{
DLT_REGISTER_APP("LOG","Test Application for Logging");

DLT_REGISTER_CONTEXT(mycontext,"TEST","Test Context for Logging");
...
}

Important note: If your application uses fork(), you may not call DLT_REGISTER_APP before fork(). And fork() should never be called after DLT_REGISTER_APP. This is because of state information and inter process communication channel to daemon would be copied to new process, but threads would be not.

Use one of the DLT macros or the DLT function interface:
Here we use the macro interface of DLT

DLT_LOG(mycontext,DLT_LOG_WARN,DLT_INT(5),DLT_STRING("This is a warning"));
DLT_LOG(mycontext,DLT_LOG_INFO,DLT_INT(5),DLT_STRING("But this only information"));

Unregister the application and the context which are registered

DLT_UNREGISTER_CONTEXT(mycontext);
DLT_UNREGISTER_APP();

Logging example
gedit dltdemo.c &
Copy the example code below into dltdemo.c
gcc -o dltdemo -ldlt dltdemo.c
rolf.haimerl|./dltdemo
DLT - Hello world

#include <stdio.h>
#include <dlt/dlt.h>
DLT_DECLARE_CONTEXT(mycontext);
int main()
{
   int num;

   DLT_REGISTER_APP("MYAP","My Application");
   DLT_REGISTER_CONTEXT(mycontext,"MYCT", "My Context");

   printf("Hello world");

   for(num=0;num<10;num++) {
      DLT_LOG(mycontext,DLT_LOG_INFO,DLT_STRING("Hello world"),DLT_INT(num));
      sleep(1);
   }

   DLT_UNREGISTER_CONTEXT(mycontext);
   DLT_UNREGISTER_APP();
   return 0;
}