PVS-Studio warning V576 for OpenCOLLADA

struct vector
{
  double x;
  double y;
  double z;
  void write(FILE* file) const
  {
    fprintf(file,"%f %f %f %f", x, y, z);
  }
};

This suspicious code was found in OpenCOLLADA project by PVS-Studio static code analyzer.
Warning message is:
V576 Incorrect format. A different number of actual arguments is expected while calling 'fprintf' function. Expected: 6. Present: 5. mayadmtypes.h 657

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/