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Binary Files

To access a file in binary mode, it must be opened with the OPEN statement. When it is no longer needed, and before the program ends, it must be closed with the CLOSE statement. See also: Filedialog, File Operations, Path and Filename.

In binary access mode, bytes are written to the file or read from the file as characters. See Chr$( n ). Use the SEEK command to seek to the desired point in the file for reading or writing. This sets the file pointer to the location specified. Use the LOC(#handle) function to retrieve the current position of the file pointer. The current position of the file pointer is used when reading or writing data to a binary file.

Data is read from the file with the INPUT statement.

Data is written to the file with the PRINT statement. Binary mode never writes line delimiters when printing to the file. Line delimiters include carriage returns, which are chr$(13) and line feeds, which are chr$(10).

Usage:

'binary file access

open "myfile.ext" for binary as #handle

'seek to file position

seek #handle, fpos

'get the current file position

fpos = loc(#handle)

'write a byte to the file

print #handle, chr$(143)

'read the data at the current location

input #myfile, txt$

Example Program:

'binary file example

open "myfile.bin" for binary as #myfile

txt$ = "I like programming with Liberty BASIC."

print "Original data in file is: ";txt$

'write some data to the file

print #myfile, txt$

'retrieve the position of the file pointer

nowPos = LOC(#myfile)

'move the filepointer

nowPos = nowPos - 14

seek #myfile, nowPos

'read the data at the current location

input #myfile, txt$

'print txt$ in mainwin

print "Data at ";nowPos;" is: ";txt$

'move the filepointer

seek #myfile, 2

'write some data to the middle of the file

print #myfile, "love"

print str$(loc(#myfile) - 2); " bytes written"

'move the file pointer to the beginning

seek #myfile, 0

'read the data

input #myfile, txt$

'print data in mainwin

print "New Data is: ";txt$

'close the file

close #myfile

end