# FILNAM
> [HTML Version](filnamsbr.htm)
**xcall FILNAM, ch, filename**
FILNAM returns _filename_ when only the file channel is known. This is frequently useful in conjunction with error trapping, where the trapping routine identifies the file only by channel.
**Parameters**
_ch_ ([Num](num.htm.md)) \[in\]
the channel that the file is open on
_filename_ ([String](string.htm.md)) \[out\]
will return the filename (as specified in the open statement) corresponding to the specified file channel. If no file is open on that channel, _filename_ returns a null string.