Question

It turns out that the following is illegal in fortran 77:

c
      program main
      real a
      parameter(a=(10.)**(.5))
c
...

The reason is because the parameter statement takes a constant arithmetic expression and exponentiation is illegal except when the exponent is an integer. (Section 6.1.3 and 8.6 http://www.fortran.com/F77_std/rjcnf0001-sh-8.html#sh-8.6 ). Does anybody know if this restriction has be relaxed in newer revisions of the standard? Why would this be illegal in the first place?

Answer 1

Yes, this has been relaxed. In Fortran 2003 you can even use intrinsic functions like sin or exp.