QApplication changes behaviour of system functions like scanf...

After creating a new QApplication the behaviour for handling the decimal point in standard library functions like sscanf, fscanf, ... is changed.
Before the QApplication is created a dot will be used as decimal point and after creating the QApplication a coma will be used.
This effects only the linux version not the windows version of Qt.
The language profile for the system must be set to a language that uses a coma as decimal point e.g. a german layout.

#include <QApplication>
#include <stdio.h>

int main(int argc, char *argv[])
{
  char xxx[]="3.212 -1.23";
  float x=0.0f;
  float y=0.0f;
  sscanf(xxx, "%f %f", &x,&y);
  printf("Read the following values %f %f\n", x,y);
  x=0.0f;
  y=0.0f;

  QApplication app(argc, argv);
  sscanf(xxx, "%f %f", &x,&y);
  printf("Read the following values %f %f\n", x,y);
  return 1;
}

--> The code produces
Read the following values 3.212000 -1.230000
Read the following values 3,000000 0,000000

on my system.

My current workaround for this is to set the LC_NUMERIC to posix after the QApplication has been created
setlocale(LC_NUMERIC, "POSIX");

Maybe it is a bug in Ubuntu as well that the LC_NUMERIC variable is not set by default, but anyway, the creation of a QApplication object shouldn't change the program behaviour.

Regards,
Benny