Exists - Revision history

Laura at 17:17, 22 May 2014

2014-05-22T17:17:43Z

← Older revision		Revision as of 17:17, 22 May 2014
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	Exists(<filename>$)		Exists(<filename>)

	The '''exists''' [[internal function]] returns a nonzero value if the specified file exists and the user has read privileges. If one or both of these conditions is false, exists returns a value of zero. NOTE that on single-user systems, all files have read privileges for the current user.		The '''exists''' [[internal function]] returns a nonzero value if the specified file ([[PROC]] or program)exists and the user has read privileges. If one or both of these conditions is false, exists returns a value of zero. NOTE that on single-user systems, all files have read privileges for the current user.

	The exists function returns:		The exists function returns:

Laura at 19:30, 21 May 2014

2014-05-21T19:30:53Z

← Older revision		Revision as of 19:30, 21 May 2014
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	Exists(filename$)		Exists(<filename>$)

	The '''exists''' [[internal function]] returns a nonzero value if the specified file exists and the user has read privileges. If one or both of these conditions is false, exists returns a value of zero. NOTE that on single-user systems, all files have read privileges for the current user.		The '''exists''' [[internal function]] returns a nonzero value if the specified file exists and the user has read privileges. If one or both of these conditions is false, exists returns a value of zero. NOTE that on single-user systems, all files have read privileges for the current user.

John: moved EXISTS to Exists over redirect

2014-02-27T13:10:10Z

moved EXISTS to Exists over redirect

← Older revision	Revision as of 13:10, 27 February 2014
(No difference)

Mikhail.zheleznov: *

2012-01-24T10:50:30Z

← Older revision		Revision as of 10:50, 24 January 2012
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	The '''exists''' [[internal function]] returns a nonzero value if the specified file exists and the user has read privileges. If one or both of these conditions is false, exists returns a value of zero. NOTE that on single-user systems, all files have read privileges for the current user.		The '''exists''' [[internal function]] returns a nonzero value if the specified file exists and the user has read privileges. If one or both of these conditions is false, exists returns a value of zero. NOTE that on single-user systems, all files have read privileges for the current user.

	The exists function ~~now~~ returns:		The exists function returns:
	*a value of 1 for directories		* a value of 1 for directories
	*a number greater than 1 for files		* a number greater than 1 for files

	====Comments and Examples====		====Comments and Examples====
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	{{Future\|Future releases of [[Business Rules!]] may return the file type (e.g., 4 for internal, 9/10/11 for programs).}}		{{Future\|Future releases of [[Business Rules!]] may return the file type (e.g., 4 for internal, 9/10/11 for programs).}}

	For the present, do not test for any specific positive value~~; only~~ zero or non-zero tests should be used. Recommended coding practices for programs are:		For the present, do not test for any specific positive value. Only zero or non-zero tests should be used. Recommended coding practices for programs are:

	00010 IF EXISTS("filename") THEN GOTO FOUND		00010 IF EXISTS("filename") THEN GOTO FOUND
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	====Related Functions====		====Related Functions====

	For additional information about files, see the following functions:		For additional information about files, see the following functions:
	*[[File]]		*[[File (internal function)]]
	*[[File$]]		*[[File$]]
	*[[FileNum]]		*[[FileNum]]
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	====Technical Considerations====		====Technical Considerations====
	# Due to anticipated enhancements for this function, it is strongly recommended that you use only zero or nonzero tests in your code~~; do~~ not attempt to test for a specific nonzero value.		# Due to anticipated enhancements for this function, it is strongly recommended that you use only zero or nonzero tests in your code. Do not attempt to test for a specific nonzero value.

	<noinclude>		<noinclude>
	[[Category:Internal Functions]]		[[Category:Internal Functions]]
	</noinclude>		</noinclude>

Mikhail.zheleznov: moved Exists to EXISTS

2012-01-17T10:12:02Z

moved Exists to EXISTS

← Older revision	Revision as of 10:12, 17 January 2012
(No difference)

Mikhail.zheleznov: 1 revision

2012-01-15T14:11:49Z

1 revision

New page

Exists(filename$)

The '''exists''' [[internal function]] returns a nonzero value if the specified file exists and the user has read privileges. If one or both of these conditions is false, exists returns a value of zero. NOTE that on single-user systems, all files have read privileges for the current user.

The exists function now returns:
*a value of 1 for directories
*a number greater than 1 for files

====Comments and Examples====

{{Future|Future releases of [[Business Rules!]] may return the file type (e.g., 4 for internal, 9/10/11 for programs).}}

For the present, do not test for any specific positive value; only zero or non-zero tests should be used. Recommended coding practices for programs are:

00010 IF EXISTS("filename") THEN GOTO FOUND
00020 IF EXISTS("filename") <> 0 THEN GOTO FOUND
00030 IF NOT EXISTS("filename") THEN GOTO NOTFOUND
00040 IF EXISTS("filename") = 0 THEN GOTO NOTFOUND

====Recommended coding practices for procedures====

SKIP FOUND IF EXISTS(filename)
SKIP FOUND IF EXISTS(filename) <> 0
SKIP NOTFOUND IF NOT EXISTS(filename)
SKIP NOTFOUND IF EXISTS(filename) = 0

====Related Functions====
For additional information about files, see the following functions:
*[[File]]
*[[File$]]
*[[FileNum]]
*[[FreeSp]]
*[[KLn]]
*[[KPs]]
*[[KRec]]
*[[LRec]]
*[[Rec]]
*[[RLn]]

====Technical Considerations====
# Due to anticipated enhancements for this function, it is strongly recommended that you use only zero or nonzero tests in your code; do not attempt to test for a specific nonzero value.

<noinclude>
[[Category:Internal Functions]]
</noinclude>