super gut!
schon das erste Beispielprogramm funktioniert auf Anhieb!

Code:
if (system("ping -c1 -s1 www.google.com"))
    {
        cout<<"There is no internet connection  \n";
}


perfekt!

Tausend Dank!

- - - Aktualisiert - - -

so, isch 'abe fertig!

jetzt kann ich mit diesen Programmfunktionen die Internet-Verbindung überprüfen und die augenblickliche Systemzeit vorformatiert abfragen

Code:
#include <iostream>
#include <stdio.h>
#include <time.h>
#include <string.h>


void getdatetime(int &year, int &mon, int &day, int &hour, int &min, int &sec, int &dow) {
   time_t t = time(NULL);
   struct tm  tm = * localtime(&t);	
   
   year = (int)tm.tm_year+1900-2000, 
   mon  = (int)tm.tm_mon+1;
   day  = (int)tm.tm_mday;
   hour = (int)tm.tm_hour;
   min  = (int)tm.tm_min;
   sec  = (int)tm.tm_sec;
   dow  = (int)tm.tm_wday+1;   
     	
}


int main()
{
   char sbuf[100];	
   
   int year, mon, day, hour, min, sec, dow;

   
   if (system( "ping -c1 -s1 www.google.de") ) {
	  printf("internet connx failed \n");
   }
   else {
	  printf("internet connx OK ! :) \n");
   }   
   
   getdatetime(year, mon, day, hour, min, sec, dow) ;
   sprintf( sbuf, "%d %d %d %d %d %d %d", year, mon, day, hour, min, sec, dow ); 
   printf(sbuf);
   
   getchar();
   return 0;
}
und die ermittelten date/time Integerwerte dann verwenden, um ggf meine RTC nicht nur manuell, sondern auch automatisch per inet zu synchronisieren....

Code:
/*
 * 
 * RTC DS3231
 * 
 * test demo
 * ver 0001
 * 
 */
 
 
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <linux/i2c-dev.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>

#include <wiringPi.h>
#include <wiringPiI2C.h>

#define  byte  uint8_t
 
// RTC DS3231
#define ADDR_RTCDS3231 0x68
int     frtcds3231;



//=====================================================================================
// Convert normal decimal numbers to binary coded decimal
//=====================================================================================
byte decToBcd(byte val) {  return( (val/10*16) + (val%10) );  }


//=====================================================================================
// Convert binary coded decimal to normal decimal numbers
//=====================================================================================
byte bcdToDec(byte val)  {  return( (val/16*10) + (val%16) ); }


//=====================================================================================




void setDS3231time( byte year, byte month, byte dayOfMonth, byte hour, byte
minute, byte second, byte dayOfWeek)
{
  // sets time and date data to DS3231  
  
  wiringPiI2CWriteReg8(frtcds3231, 0, decToBcd(second));      // set seconds
  wiringPiI2CWriteReg8(frtcds3231, 1, decToBcd(minute));      // set minutes
  wiringPiI2CWriteReg8(frtcds3231, 2, decToBcd(hour));        // set hours
  wiringPiI2CWriteReg8(frtcds3231, 3, decToBcd(dayOfWeek));   // ( 1=Sunday, 7=Saturday)
  wiringPiI2CWriteReg8(frtcds3231, 4, decToBcd(dayOfMonth));  // set dayOfMonth (1 to 31)
  wiringPiI2CWriteReg8(frtcds3231, 5, decToBcd(month));       // set month
  wiringPiI2CWriteReg8(frtcds3231, 6, decToBcd(year));        // set year (0 to 99)
   
}


//=====================================================================================



int main() {
   int  year, month, dayOfMonth, hour, minute, second, dayOfWeek;   
   int i=0, check;
   char sbuf[100];   

   frtcds3231 = wiringPiI2CSetupInterface( "/dev/i2c-0",  ADDR_RTCDS3231 );	   
   
   printf(" RTC DS3231 \n");
   printf("Set new Date/Time:   enter 1\n");
   printf("else:   display time\n\n");

   i = getchar();
   
   //debug
   //printf("%d \n", i);
   
   while (i=='1') {
      // get string yy mm dd hh mm ss dw : gets() ?
      printf("yy mm dd hh mm ss dw (DayOfWeek) \n");
      check=scanf("%d %d %d %d %d %d %d", &year, &month, &dayOfMonth,  &hour, &minute, &second, &dayOfWeek);
      
      getchar();
      printf("check=%d\n", check);
      
      if(check==7) {     
		 printf("%d \n", year); 
		 printf("%d \n", month); 
		 printf("%d \n", dayOfMonth); 
		 printf("%d \n", hour); 
		 printf("%d \n", minute); 
		 printf("%d \n", second); 
		 printf("%d \n", dayOfWeek); 
         setDS3231time( year, month, dayOfMonth, hour, minute, second, dayOfWeek );
      }             
      
      printf(" RTC DS3231 \n");
      printf("Set new Date/Time:   enter 1\n");
      printf("else:   display time\n\n");
      i=0;
      i = getchar();
            
   }
   

 
   while(1) {
     second =     bcdToDec(wiringPiI2CReadReg8 (frtcds3231, 0) & 0x7f );
     minute =     bcdToDec(wiringPiI2CReadReg8 (frtcds3231, 1) );
     hour =       bcdToDec(wiringPiI2CReadReg8 (frtcds3231, 2) & 0x3f );
     dayOfWeek =  bcdToDec(wiringPiI2CReadReg8 (frtcds3231, 3) );
     dayOfMonth = bcdToDec(wiringPiI2CReadReg8 (frtcds3231, 4) );
     month =      bcdToDec(wiringPiI2CReadReg8 (frtcds3231, 5) );
     year =       bcdToDec(wiringPiI2CReadReg8 (frtcds3231, 6) );  
	 -
     sprintf(sbuf, "20%02d/%02d/%02d  %02d:%02d:%02d", year, month, dayOfMonth, hour, minute, second); 
     printf(sbuf);
     
     printf(" Day of week %1d: ", dayOfWeek);
     switch(dayOfWeek){
     
     case 1:
       printf("Sunday");
       break;
     case 2:
       printf("Monday");
       break;
     case 3:
       printf("Tuesday");
       break;
     case 4:
       printf("Wednesday");
       break;
     case 5:
       printf("Thursday");
       break;
     case 6:
       printf("Friday");
       break;
     case 7:
       printf("Saturday");
       break;
     }
     printf("\n");		
     
     delay (1000);	     
     
	    	 
  }

  return (0);
}
das war der Sinn des ganzen!

tausend Dank nochmal Mxt für deine Hilfe!