Microsoft KB Archive/104776

= BUG: Endless Loop in Code Containing Graphics & Compiled -Ox =

Article ID: 104776

Article Last Modified on 10/2/2003

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APPLIES TO


 * Microsoft FORTRAN PowerStation 1.0 Standard Edition
 * Microsoft Fortran PowerStation 1.0a for MS-DOS

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This article was previously published under Q104776



SYMPTOMS
A program may execute in an infinite loop if it was compiled with full optimization (-Ox) and contains a do loop calling some of the graphics routines [such as POLYGON_W].



CAUSE
Some of the graphics functions (such as POLYGON_W) prevent optimized code from recognizing the end condition for the loop.



STATUS
Microsoft has confirmed this to be a problem in FORTRAN PowerStation for MS-DOS, version 1.0 and 1.0a.

This problems does not apply to FORTRAN PowerStation 32.



RESOLUTION
Compile the program with no optimization (this is the default).

Sample Code
c Compile options needed:   -Ox c The following program will output in an infinite loop:

include 'fgraph.fi' include 'fgraph.fd' INTEGER*2 status, npts

RECORD    / wxycoord /  wxyarr(3)

status = setvideomode(18) do it=1,2 write (*,'(i4\)') it        wxyarr(1).wx = 43.d0         wxyarr(1).wy = 85.d0         wxyarr(2).wx = 50.d0         wxyarr(2).wy = 71.d0         wxyarr(3).wx = 45.d0         wxyarr(3).wy = 85.d0         npts = 3 status = POLYGON_W($GBORDER, wxyarr, npts) enddo END

Additional query words: nofpsnt 1.00

Keywords: KB104776

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