[petsc-users] Warning [-Wformat-overflow]

I have warning: FormatFunction.c: In function 'ComputeStiffnessMatrix': FormatFunction.c:128:46: warning: '%d' directive writing between 1 and 11 bytes into a region of size between 0 and 99 [-Wformat-overflow] (line128) sprintf(filename, "%sc%d_N%dM%d_permeability.log", up->problem_description, up->problem_flag, up->Nx, up->Mx) do you know why this warning appear? and how to fix it. -- Best regards, --