TRAPOV(3F)                           BSD                            TRAPOV(3F)



NAME
     trapov - trap and repair floating point overflow

SYNOPSIS
     subroutine trapov (numesg, rtnval)
     double precision rtnval

DESCRIPTION
     NOTE: This routine applies only to the older VAX 11/780's.  VAX computers
     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 and
     Apollo workstations.

     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()".

FILES
     /usr/lib/libF77.a

SEE ALSO
     trpfpe(3F), signal(3F), range(3F)

BUGS
     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.