Software » Campo » Biwak

h1. Logging

There is no clean logging concept at the moment.

* Low footprint

* Work within ISRs. The output is delayed. The order is preserved.

* Only short messages, e.g. 20 chars. 

* Heart-beat LED might be involved

* CAN might be involved to transmit diagnose

* Debug can be disabled even for Debug-builds; BIWAK_LOG_DEBUG has to be defined to show bDebug

h2. Heartbeat-Class

An LED can indicate problems.

* good (double heartbeat)

* critical error/ exception (fast blink)

* fatal error (slow blink)

* temporary error/ trouble (fast blink - off 1Hz) (goes away)

h2. Usecases

* invalid eeprom causes "critical"-state

* Not being able to sen CAN messages causes "trouble"

* fatal: the application can not run for some reason but the led should work; e.g. a reception buffer is full

* exception: Don't even try to run any more. e.g. memory error.

h2. Notes

There is already a doublebuffer-class for CAN.

h2. Examples

<pre><code class="cpp">

add_definitions( BIWAK_LOG_HEARTBEAT )

add_definitions( BIWAK_LOG_CAN )

add_definitions( BIWAK_LOG_DEBUG )

#define bDebug(a,...) debug(a, __VA_ARGS__)

</code></pre>

<pre><code class="cpp">

#include <biwak/log.hpp>

main()

{

   bDebug();      // Just print some text

   bCritical();

   bTrouble();    // 

   bFatal();

   bException("Static text");

}

</code></pre>

<pre><code class="cpp">

static struct {

    char buf[20];

    bool used;

}buffers[2]={0};

void bWarning(const char *text, ...)

{

    va_list list;

    va_start(list, text);

    int bufid;

    for(bufid=0; bufid < ARRAY_ELEMENTS(buffers); bufid++)

    {

        if(!buffers[bufid].used)

        {

            break;

        }

    }

    if(bufid >= ARRAY_ELEMENTS(buffers))

    {

        bException("Out of log buffers!");

    }

    buffers[bufid].used=true;

    vsnprintf(buffers[bufid].buf, 20, text, list);

    puts(buffers[bufid].buf);

    printf("Bufid: %d; elements: %d\n", bufid, ARRAY_ELEMENTS(buffers));

};

</code></pre>