Using FoxPro to Check for Existence of a Directory

  • Article

This article describes how to use FoxPro to Check for Existence of a Directory.

Original product version:   Visual FoxPro
Original KB number:   94339

Summary

There are two ways to check for the existence of a directory on a drive:

  • The FILE() function can be used to check for the existence of a file on a local drive. FILE() only works on network drives under work groups.

    Note

    The method described below using the FILE() function does not work when running FoxPro for Windows or FoxPro for MS-DOS under Windows 3.11. This method can only be used when running FoxPro for MS-DOS directly under MS-DOS versions greater than 3.0, or when running FoxPro for MS- DOS or FoxPro for Windows under Windows NT.

  • The ADIR() and ASCAN() functions can be used together to check for the existence of a file on either a local or network drive.

More information

FILE() attempts to locate a file or directory on disk and returns .T. or .F. based on the results of the search. Specify the filename to search for as a character string argument. To test for the existence of a directory, specify NUL as the filename. For example:

?FILE('c:\temp\NUL')

The above command checks for the existence of the C:\FOXPRO2 directory.

Note

This usage of NUL is not supported by versions of MS-DOS prior to version 3.0.

ADIR() places file information in an array. The resulting array contains five columns, containing filenames, sizes, dates, times, and attributes, respectively. ADIR() takes up to three arguments:

  • <expC1> indicates the array name.

  • <expC2> is optional and can be used to specify a template filename, such as C:\FOX* or *.DBF. Only filenames matching the template will be placed in the array.

  • <expC3> can contain the letters D, H, S, or V to limit the results to directory names, hidden files, system files, or the volume name, respectively.

The ASCAN() function can then be used to determine if a matching directory entry was placed in the array. For example:

?ADIR(dirarray,'FOXPRO2','D')

The above command creates the array named dirarray and creates one row for the directory FOXPRO2.

?ASCAN(dirarray,'FOXPRO2')

The above command returns .T. or .F. if FOXPRO2 is contained in the array.

References

For more information on FILE(), ADIR(), and ASCAN(), see the FoxPro version 2.0 "Commands & Functions" manual or the FoxPro version 2.5 "Language Reference" manual.