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LOF

Syntax

LOF(file number)

Versions: Disk

Description

Returns the length of the file associated with the specified file number, in bytes. The file must be currently open.

LOF is useful for: - Determining file size before reading - Allocating space for file contents - Validating file sizes - Computing file positions and offsets

Example

10 OPEN "DATA.TXT" FOR INPUT AS #1
20 PRINT "File size:"; LOF(1); "bytes"
30 CLOSE #1
Ok

10 OPEN "R", #1, "RANDOM.DAT", 128
20 RECORDS = LOF(1) / 128
30 PRINT "File contains"; RECORDS; "records"
40 CLOSE #1

Notes

  • The file number must refer to an open file
  • Returns the total file size, not the current position
  • For random access files, divide by record length to get record count

See Also

  • CLOSE - To conclude I/O to a disk file
  • EOF - Returns -1 (true) if the end of a sequential file has been reached
  • FIELD - To allocate space for variables in a random file buffer
  • FILES - Displays the directory of files on disk
  • GET - To read a record from a random disk file into a random buffer
  • INPUT$ - Returns a string of X characters, read from the terminal or from file number Y
  • LOC - Returns current file position/record number (LOF returns total size in bytes)
  • LPOS - Returns the current position of the line printer print head within the line printer buffer
  • LSET - Left-justifies a string in a field for random file output
  • OPEN - To allow I/O to a disk file
  • POS - Returns the current cursor position
  • PRINTi AND PRINTi USING - To write data to a sequential disk file
  • PUT - To write a record from a random buffer to a random file
  • RESET - Closes all open files
  • RSET - Right-justifies a string in a field for random file output
  • WRITE # - Write data to a sequential file with delimiters
  • LINE INPUT# - To read an entire line (up to 254 characters), without delimiters, from a sequential disk data file to a string variable