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Annotation of 43BSDTahoe/man/man3f/trapov.3, revision 1.1.1.1

1.1       root        1: .\" Copyright (c) 1983 Regents of the University of California.
                      2: .\" All rights reserved.  The Berkeley software License Agreement
                      3: .\" specifies the terms and conditions for redistribution.
                      4: .\"
                      5: .\"    @(#)trapov.3f   6.1 (Berkeley) 5/15/85
                      6: .\"
                      7: .TH TRAPOV 3F "May 15, 1985"
                      8: .UC 5
                      9: .SH NAME
                     10: trapov \- trap and repair floating point overflow
                     11: .SH SYNOPSIS
                     12: .B subroutine trapov (numesg, rtnval)
                     13: .br
                     14: .B double precision rtnval
                     15: .SH DESCRIPTION
                     16: \fBNOTE: This routine applies only to the older VAX 11/780's.
                     17: VAX computers made or upgraded since spring 1983 handle errors differently.\fR
                     18: See
                     19: .IR trpfpe (3F)
                     20: for the newer error handler.
                     21: This routine has always been ineffective on the VAX 11/750.
                     22: It is a null routine on the PDP11.
                     23: .PP
                     24: This call sets up signal handlers to trap arithmetic exceptions
                     25: and the use of illegal operands.
                     26: Trapping arithmetic exceptions allows the user's program to proceed from
                     27: instances of floating point overflow or divide by zero.
                     28: The result of such operations will be an illegal floating point value.
                     29: The subsequent use of the illegal operand will be trapped
                     30: and the operand replaced by the specified value.
                     31: .PP
                     32: The first
                     33: .I numesg
                     34: occurrences of a floating point arithmetic error will cause a message
                     35: to be written to the standard error file.
                     36: If the resulting value is used, the value given for
                     37: .I rtnval
                     38: will replace the illegal operand generated by the arithmetic error.
                     39: .I Rtnval
                     40: must be a double precision value. For example, ``0d0'' or ``dflmax()''.
                     41: .SH FILES
                     42: .ie \nM /usr/ucb/lib/libF77.a
                     43: .el /usr/lib/libF77.a
                     44: .SH SEE ALSO
                     45: trpfpe(3F), signal(3F), range(3F)
                     46: .SH BUGS
                     47: Other arithmetic exceptions can be trapped but not repaired.
                     48: .PP
                     49: There is no way to
                     50: distinguish between an integer value of 32768 and the illegal
                     51: floating point form.
                     52: Therefore such an integer value may get replaced while repairing
                     53: the use of an illegal operand.

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