TRAPOV(3F)                                                          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 comput‐‐
       ers made or upgraded since spring 1983 handle errors differently.   See
       _t_r_p_f_p_e(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 _n_u_m_e_s_g 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 _r_t_n_v_a_l will replace the
       illegal operand generated by the arithmetic error.  _R_t_n_v_a_l  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.



4.2 Berkeley Distribution        May 15, 1985                       TRAPOV(3F)