## The directory-specification utility FDCDIR

FDCDIR is a utility that builds pathnames for subdirectories of the FDC toolbox. It is called by several other programs from the toolbox to determine file-locations.

Due to the fact that the FDC root-directory will be different on different systems, referencing FDC subdirectories can be difficult. To facilitate this, the function FDCDIR was constructed. Calling this function for a user-specified FDC subdirectory will result in a complete path to this directory, that is: the subdirectory will be enhanced with the root-directory of the FDC toolbox.

If the resulting pathname does not exist, a warning message will be displayed. There are two possible causes for this condition to occur:

1. the specified FDC subdirectory or the currently used root-directory is invalid,
2. the specified root or subdirectory can't be found because it has been deleted or moved to another location. The location of the FDC root-directory will be obtained from the file `fdc.ini`. If that file can't be found, FDCDIR will try the default FDC root-location `MATLABROOT\toolbox\fdc14`.

### Usage

`D = fdcdir` returns the root-directory of the FDC toolbox and stores it in the string-variable D.

`D = fdcdir(NAME)` returns the complete path of the FDC subdirectory specified in the string-variable NAME to the string variable D.

`D = fdcdir(NAME1,NAME2)` returns the complete path of the FDC sub-subdirectory specified in the string-variable NAME2, which itself is contained in the FDC subdirectory specified in the string-variable NAME2 (see the example below).

More input arguments are allowed (but not very practical), as long as the inputs are all string variables.

### Examples

Suppose we call FDCDIR with the following command:
`D = fdcdir('MODELS')`
and `C:\MATLAB\TOOLBOX\FDC14` is specified as root-directory in the file `fdc.ini`. This yields:
`D = 'C:\MATLAB\TOOLBOX\FDC14\MODELS'`.

Using this same root-directory, the command:
`D = fdcdir('MODELS','AIRCRAFT')`
will yield:
`D = 'C:\MATLAB\TOOLBOX\FDC20\MODELS\AIRCRAFT'`.

Note: even though Windows notation has been used for the pathnames in the examples and information above, the program itself makes use of generic path and file-separators.

### Related utilities

The macro's DATADIR and HELPDIR make use of this function to specify the FDC data-directory and the location of the on-line helpfiles, respectively.