File (internal function)
File(<file handle>)
The File internal function returns the numeric value that specifies the status of file associated with the File Handle.
| -1 | File not opened. |
| 0 | Operation performed successfully. |
| 10 | End of file occurred during input. |
| 11 | End of file occurred during output. |
| 20 | Transmission error during input. |
| 21 | Transmission error during output. |
Comments and Examples
Print File(N) will return -1 when the file N is not opened. File(N) can be used to separate input from output errors in file processing, including communications files.
Window Interrogation
Using file with the optional parameters, WINDOW_RECT or USABLE_RECT allows BR to distinguish between window dimensions and the useable area of windows.
file(nn,"WINDOW_RECT | USABLE_RECT", MAT num-arrayname)
The above file() reference redimensions num-arrayname to 4 elements and returns X (horizontal), Y (vertical), Width, and Height in pixels of either the window or usable area rectangle.
Fontsize
Using File with FONTSIZE returns a two element array with the height and width of each fixed character position in pixels (used for positioning and sizing controls). For example:
file(N,"FONTSIZE", MAT num-arrayname)
extended syntax examples
file(101,'WINDOW_RECT',mat x)
returns 4 items in mat x
- x(1)=left
- x(2)=top
- x(3)=width
- x(4)=height
See Also
For additional information about files, see the following: