tlm_api_cpp_newest/cpp_newest_main.cpp

#include <stdio.h>
#include "telemetry_api.h"
#include "parameter.h"
#include "packet.h"

//
//  NOTE:  This example requires the TReK Data GUI to be started and the PDSS Payload
//  Packet with APID 7 to be activated with a Real-Time data mode.
//

using namespace trek;

int main()
{
    TelemetryApi tlm_api;
    StringArray pkt_key_list;
    Packet pkt;
    uint8_t buf[4096];
    uint32_t buf_len;
    uint32_t token = 0;     // always initialize the token to zero
    int ret_value;

    //
    //  Connect to a data store.
    //

    ret_value = tlm_api.Connect("DefaultDataStore");

    if( ret_value )
    {
        printf( "Error %d:  Could not connect to data store.\n", ret_value );
        return 1;
    }

    //
    //  Calling this method allows the API to clean up resources that may be
    //  left over from a user program that crashed.  Not checking the return
    //  value as it is safe to continue if this method fails.
    //

    tlm_api.Cleanse();

    //
    //  Get a list of the packet keys currently being processed.  If you know
    //  your packet key already, this isn't needed.
    //

    ret_value = tlm_api.GetSourceList( pkt_key_list );

    if( ret_value )
    {
        printf( "Error %d:  Could not get packet list.\n", ret_value );
        return 1;
    }

    for( uint32_t ii = 0; ii < pkt_key_list.Size(); ii++ )
        printf( "Packet key %u: %s\n", ii+1, pkt_key_list.GetAt(ii) );

    //
    //  Get the packet definition so that parameters can be extracted
    //  from the packet.
    //

    ret_value = tlm_api.GetPacketDefinition( "PdssPayload.RT.PL.7", pkt );

    if( ret_value )
    {
        printf( "Error %d:  Could not get packet definition.\n", ret_value );
        return 1;
    }

    //
    //  Get the latest packet from the data store.
    //

    buf_len = 4096;     // always reset this value for each call
    ret_value = tlm_api.GetNewestPacket( "PdssPayload.RT.PL.7", token, buf, buf_len );

    if( ret_value )
    {
        printf( "Error %d:  Could not get the latest packet.\n", ret_value );
        return 1;
    }

    //
    //  Use the packet definition to extract the data.
    //

    uint32_t last_bit_used;
    ret_value = pkt.Extract( buf, buf_len, last_bit_used );

    if( ret_value )
    {
        printf( "Error %d:  Could not extract parameter data from the packet.\n", ret_value );
        return 1;
    }

    //
    //  The packet has been extracted and can now get the values using the Packet class
    //  methods.  Look up a parameter and get its value.
    //

    Parameter *param_ptr;
    ret_value = pkt.FindParameter( "MSID016", &param_ptr );

    if( ret_value )
    {
        printf( "Error %d:  Could not find parameter.\n", ret_value );
        return 1;
    }

    int32_t int_value;
    ret_value = param_ptr->GetValue( int_value );

    if( ret_value )
    {
        printf( "Error %d:  Could not get parameter value.\n", ret_value );
        return 1;
    }

    printf( "Value is: %d.\n", int_value );

    //
    //  It is always best to call Disconnect when you are finished with the
    //  API.  There are system resources that can be freed when you no 
    //  longer need the API.
    //

    ret_value = tlm_api.Disconnect();

    if( ret_value )
    {
        printf( "Error %d:  API did not disconnect properly.\n", ret_value );
        return 1;
    }

    return 0;
}