trapov - trap and repair floating point overflow
subroutine trapov (numesg, rtnval)
double precision rtnval
NOTE: This routine applies only to the older VAX 11/780's. VAX comput-
ers made or upgraded since spring 1983 handle errors differently. See
trpfpe(3F) for the newer error handler. This routine has always been
ineffective on the VAX 11/750. It is a null routine on the PDP11.
This call sets up signal handlers to trap arithmetic exceptions and the
use of illegal operands. Trapping arithmetic exceptions allows the
user's program to proceed from instances of floating point overflow or
divide by zero. The result of such operations will be an illegal
floating point value. The subsequent use of the illegal operand will
be trapped and the operand replaced by the specified value.
The first numesg occurrences of a floating point arithmetic error will
cause a message to be written to the standard error file. If the
resulting value is used, the value given for rtnval will replace the
illegal operand generated by the arithmetic error. Rtnval must be a
double precision value. For example, ``0d0'' or ``dflmax()''.
trpfpe(3F), signal(3F), range(3F)
Other arithmetic exceptions can be trapped but not repaired.
There is no way to distinguish between an integer value of 32768 and
the illegal floating point form. Therefore such an integer value may
get replaced while repairing the use of an illegal operand.
4th Berkeley Distribution 18 July 1983 TRAPOV(3F)