On Fri, Jan 26, 2024 at 03:44:26PM +0200, Elias Toivanen wrote: > > I stumbled upon a Fortran quirk regarding the ranges for integers. > The standard stipulates that the ranges be symmetric even though > as we know two's complement signed integers have asymmetrical > ranges, e.g. int8 kind can vary between -128 and 127.
This is not quite true. The model number for integer is symmetric, but the machine representable does not need to be symmetric. > > This is sure to cause confusion as for example the following > program does not compile: > > ``` > program main > use iso_fortran_env > implicit none > print *, -128_int8 This is a unary minus operator with an operand of 128. gfortran does not have negative integers. > end program > ``` > > GFortran 13.2.0 provides the error message > > Error: Integer too big for its kind at (1). This check can > be disabled with the option '-fno-range-check' which gives you this error because 128 is greater 127. It is a little known fact, but you can force a symmetric range with the -pedantic option. -- Steve
