Article: Q118815
Product(s): Microsoft Fortran Compiler
Version(s): 1.0,1.0a
Operating System(s):
Keyword(s):
Last Modified: 02-NOV-1999
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The information in this article applies to:
- Microsoft FORTRAN PowerStation for MS-DOS, versions 1.0, 1.0a
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SYMPTOMS
========
When a program draws a line with an endpoint outside the screen coordinates, the
line is not clipped and the following error message is generated:
run-time error M6101: MATH
- floating-point error: invalid
CAUSE
=====
The limit seems to be related to converting to an int. In the sample code below,
the extent of X in the window coordinates is 1.0, the screen coordinate is 639,
and the line is drawn to 51.28. For example:
639 * 51.28 / 1.0 = 32,767.92 > 32,767
In the preceding example, a line drawn to 51.27 succeeds (639 * 51.27 / 1.0 =
32,761.53 < 32,767).
RESOLUTION
==========
Do not draw outside the screen coordinates. Clip the endpoints of lines before
calling the LINETO_W routine. If you clip to values within 10 times the size of
the window, the code should work in any resolution.
STATUS
======
Microsoft has confirmed this to be a bug with Microsoft FORTRAN PowerStation for
MS-DOS, versions 1.0 and 1.0a.
MORE INFORMATION
================
To demonstrate this problem, compile the following sample code and run it from a
full-screen MS-DOS prompt in Windows (not Windows NT) or directly from MS-DOS.
Sample Code
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C Compile options needed: none
INCLUDE 'FGRAPH.FI'
INCLUDE 'FGRAPH.FD'
INTEGER*2 status
status = SETVIDEOMODE( $VRES16COLOR )
status = setwindow(.TRUE.,0D0,1.D0,1.D0,0.D0 )
status = LINETO_W( 51.28d0, 0.0d0 )
status = SETVIDEOMODE( $DEFAULTMODE )
END
Additional query words: 1.00 1.00a
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Keywords :
Technology : kbAudDeveloper kbFortranSearch kbZNotKeyword3 kbFORTRANPower100DOS kbFORTRANPower100aDOS
Version : :1.0,1.0a
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