Exists

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

1. 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.