TRAPER(3F)	    UNIX Programmer's Manual	       TRAPER(3F)



NAME
     traper - trap arithmetic errors

SYNOPSIS
     integer function traper (mask)

DESCRIPTION
     NOTE: This routine applies only to the VAX.  It is ignored
     on the PDP11.

     Integer overflow and floating point underflow are not nor-
     mally trapped during execution. This routine enables these
     traps by setting status bits in the process status word.
     These bits are reset on entry to a subprogram, and the pre-
     vious state is restored on return.  Therefore, this routine
     must be called _i_n_s_i_d_e each subprogram in which these condi-
     tions should be trapped.  If the condition occurs and trap-
     ping is enabled, signal SIGFPE is sent to the process. (See
     _s_i_g_n_a_l(3C))

     The argument has the following meaning:

	     value   meaning
	       0     do not trap either condition
	       1     trap integer overflow only
	       2     trap floating underflow only
	       3     trap both the above

     The previous value of these bits is returned.

FILES
     /usr/lib/libF77.a

SEE ALSO
     signal(3C), signal(3F)




















Printed 11/26/99	  May 15, 1985				1