[Tcl-bugs] [ tcl-Bugs-218000 ] "Inf" not understood in expr

[<no...@so...>]

Bugs item #218000, was opened at 2000-10-25 17:51
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Category: 43. Parsing and Eval
Group: = 8.0p2
Status: Open
Resolution: Invalid
Priority: 2
Submitted By: Nobody/Anonymous (nobody)
>Assigned to: Don Porter (dgp)
>Summary: "Inf" not understood in expr

Initial Comment:
OriginalBugID: 680 Bug
Version: 8.0p2
SubmitDate: '1998-09-23'
LastModified: '1999-09-15'
Severity: LOW
Status: Closed
Submitter: welch
ChangedBy: hobbs
OS: All
OSVersion: NA
Machine: NA
FixedDate: '2000-10-25'
FixedInVersion: NA
ClosedDate: '1999-09-15'


I've got a program that returns the floating point number HUGE_VAL to
Tcl.  Unfortunately, libc represents this as "Inf" which Tcl cannot convert
back into a floating point number.

Here's an example:
  - "$myobj" is an instance of a class I've created
  - "$myobj hugeVal" just returns the defined constant HUGE_VAL
  - "$myobj setIt" tries to convert the parameter via Tcl_GetDouble

% $myobj hugeVal
Inf
% set val [$myobj hugeVal]
Inf
% set a [expr $val / 10]
syntax error in expression "Inf / 10"
% $myobj setIt $val
expected floating-point number but got "Inf"


The actual code for the "hugeVal" function looks like:

    case 32: {        // double hugeVal(void)
        double _retcode;

        if (_argc != 2) {
            _interp->result = "wrong # args";
            return TCL_ERROR;
        }
        _retcode = HUGE_VAL;

        sprintf(_interp->result,"%f",_retcode);
    } break;


                                          Brian
                                 ( bc...@ve... )


The problem is that sprintf does the interp here, converting
it to a regular string "Inf".  Code like this should benefit
from Tcl_Obj's, where it needn't be stored as a string. 
-- 09/15/1999 hobbs

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>Comment By: Jeffrey Hobbs (hobbs)
Date: 2002-02-25 14:16

Message:
Logged In: YES 
user_id=72656

SuSE 7.3 build of 2002-02-25 8.4 build also gives:

% expr {"INF"}
floating-point value too large to represent

That actually seems correct to me in some sense.

----------------------------------------------------------------------

Comment By: Don Porter (dgp)
Date: 2001-08-10 09:16

Message:
Logged In: YES 
user_id=80530

Re-opening this so we can address the
new HPUX comment.  Need to examine
cross-platform inconsistency of [expr]
-- probably due to inconsistency of
strtod() or something similar.

----------------------------------------------------------------------

Comment By: Nobody/Anonymous (nobody)
Date: 2001-08-10 05:51

Message:
Logged In: NO 

I wanted to add some thing more to this.
If test case like this.

tcl> set a INF
tcl>if{($a == "*")} {
}

It's giving floating-point value too large.
Please comment on this.

This is only on HPUX platform only.

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