FILNM

Return the file specification of the open channel

WSupported on Windows

USupported on Unix

VSupported on OpenVMS

NSupported in Synergy .NET

xcall FILNM(channel, file_spec[, length])

Arguments

channel

The open channel. If the channel is not open, a “Channel has not been opened” error ($ERR_NOOPEN) is generated. (n)

file_spec

The variable that will be loaded with the file specification, left-justified over blanks. (See File specifications for a description of a file specification layout.) (a)

length

(optional) The length of the filename string. (n)

Discussion

The FILNM subroutine returns the file specification of the file that is currently open on a specified channel.

The information returned by the FILNM subroutine can clarify an I/O-oriented error when it is trapped by a program. The program can report the error number, use the ERTXT subroutine to provide a description of the error, and then call FILNM to report the specification of the file involved.

If file_spec is too short to hold the entire file specification, only the leftmost portion of the specification is returned.

The FILNM subroutine of a channel opened to TT: returns TT:.

Examples

subroutine proc_error
    a_chn               ,d      ;Optional
.define TTCHN           ,1
record
    msg                 ,a45
    file                ,a80
proc
    xcall ertxt(%ernum, msg)
    writes(TTCHN, "Error# + %string(%ernum) + ": " + msg + "at line " 
  &        + %string(%erlin))
    if (^passed(a_chn))
      begin
        xcall filnm(a_chn, file)
        writes(TTCHN, "File: + file(1:%trim(file)))
      end
    return
endsubroutine