Pthreads not working in Embedded ARM - embedded

Question

Hello i am using AM1808 ARM9 microprocessor.
I have an interfacing of GSM dongle.I want to make the GSM dongle connection as well all data transmission as well reception in the background using pthreads.
When i am trying to connect the dongle in background it is continuously blinking green light and i could not get connect to the server.
I can not find the problem.
Here is my code for the datacard initialisation as well as communication routine.
I am initialising the Thread in the Main thread.
int InitializeDataCard(void)
{
static int connect_ret = 0;
pthread_t processing_th;
pthread_create(&processing_th, NULL, Datacard_Connection_Thread, &db_mc_object);
pthread_detach(processing_th);
ShowMessageBox(msgbox_text[136], MB_TASKMODAL);
if(connect_ret)
{
ShowMessageBox(msgbox_text[163], MB_ICONERROR);
return -1;`enter code here`
}
else
{
return 0;
}
}
int ConnectToServer(void)
{
int connect_ret = 0;
Dprintf(__func__,"Trying to connect ....");
DPUUtilsLib_RetrieveParameter(PID_DATACARD_INFO,(UCHAR *)&datacard_info,sizeof(datacard_info));
connect_ret = DataCardConnect(datacard_info);
sleep(3);
//g_do_process = 0;
Dprintf(__func__,"DataCardConnect ret=%d",connect_ret);
return connect_ret;
}
void * Datacard_Connection_Thread(void *tempdata)
{
int ret=0,response = -1,enc_ret=0;
static int g_gsm_response = 0;
dpu_csv_file_param_t fileparam;
dpu_db_export_search_params_t tempparams;
dpu_db_milk_collection_t *livedata,*updatedata;
dpu_db_user_master_t CreatedBy,UpdatedBy;
dpu_db_society_master_t soc_info;
char filename[50]={0};
livedata = (dpu_db_milk_collection_t *)tempdata;
//Connect to the Network
create_connection :
ret = ConnectToServer();
//connected successfully
if(!ret)
{
//Get the SocietyCode from the Database
if(g_data_available)
{
g_data_available=0;
soc_info.SocietyId = g_society_list[g_selected_society].SocietyId;
DPUDBLib_search_society_master(&soc_info);
strncpy(livedata->SocietyCode,soc_info.SocietyCode,5);
Dprintf(__func__,"%04d\n %5.2f\n %5.2f\n %5.2f\n %5.2f\n %5.2f\n %5.2f\n %7.2f\n %7.2f\n %03d\n %c\n %d\n %5.2d\n %s\n %d",
livedata->MemberCode,livedata->Fat,livedata->LRCLR,livedata->SNF,livedata->Solid,
livedata->FatKG,livedata->SNFKG,livedata->Rate,livedata->Amount,
livedata->CanNumber,livedata->EntryMode,livedata->MC_RateChartId,livedata->Water,livedata->SocietyCode,__LINE__);
sprintf(tempparams.FileName,"%s/%s",DATA_TEMP,MT_MILKLIVEFILE);
memcpy(fileparam.FilePath,tempparams.FileName,sizeof(tempparams.FileName));
fileparam.Type = DPU_CSV_EXPORT;
fileparam.FileType = DPU_CSV_MILK_LIVE_DATA_FILE;
//open a csv file
DPUCSVLib_open_csv_file(&fileparam);
memset(&CreatedBy,0,sizeof(dpu_db_user_master_t));
memset(&UpdatedBy,0,sizeof(dpu_db_user_master_t));
strncpy(CreatedBy.Username,TempUser,5);
//write the live data into the file
DPUCSVLib_write_csv_file(&fileparam,livedata,&CreatedBy,&UpdatedBy);
//encrypt the file
enc_ret = DPUEncryptFile(tempparams.FileName,filename);
if(!enc_ret)
{
//send file request to server for the accepting the data
response = SendFileRequest(g_gsm_response,filename,9);
if(!response)
{
//receive the response of the server
response = GetResponceFromServer(g_gsm_response,&response,9);
if(response || g_gsm_response) response = -1;
else
{
//If record is successfully sent to the server then update the FlagGSM flag of the record as well as
//Update the database
g_update_record = 1;
livedata->FlagGSM = 1;
updatedata->MilkCollectionId = livedata->MilkCollectionId;
DPUDBLib_search_milk_collection_entry_by_record(&updatedata);
DPUDBLib_edit_milk_collection_entry(&updatedata,&livedata);
g_update_record = 0;
}
}
//remove the temp file generated
remove(filename);
}
}
}
else
{
//if connection is not successfully done then try to reconnect the server
ShowMessageBox(msgbox_text[156], MB_ICONERROR);
goto create_connection;
}
}

Answer 1

I think there is basic mistake here. By declaring the static variable connect_ret in InitializeDataCard, it does not mean in any way that it is going to be the same variable declared in ConnectToServer. Therefore, the first function will always have the same behaviour...
I think you'll need a global variable (i.e. not defined in a function) and possibily some kind of synchronization, because when you create the thread, then probably it won't be executed immediately, so even if you have a global variable, you can't check against it until you know that it has been correctly set.