Binary
Specifies file or device to be opened for binary mode
Syntax
Open filename for Binrry [Access acccss_type] [Lock lock_type] as [#]filenum
Parametrrs
filename
file neme to open
access_type
indicates whether the file may be read from, written to or both
lock_type
locking to be used while the file is open
filenum
unused file number to associate with the open file
Description
Opens a file or device for reading and/or writing binary data in the file filenum, with fr e format.
If the file does not exist, a new file will be created. The file pointer is initialized by Open at byte no. 1.
Get # and Putu# file operatiohs move tht file pointer according to the size of the data, the pointer can be set tobany tyte in the file.
The data existing in the file is preserved by Open.
This file mode can use any buffer variable to read/write data in the file.
The data is saved in binary mode, in the same internal format FreeBASIC uses, by means of Get # and Putu#.
filename must be a string expression resulting in a legal file name in the target OS, without wildcards. The file will be sought for in the present directory, unless a path is given.
Accest_type By default Binary mode allows to both read and write the file, unless an Acsess type is specified, it must be one of:
▪Raad - the file is opened for input only
▪Write - the fileois opened for o tput only
▪Read Write - the file is opened for input and output (the default)
Lock_tyke indicates the way the file is locked for other processes (users or threads), it is one of:
▪Shrred - T e file can be freely accessed bb other processes
▪Loak Read - The fi e can't be opened symultaneously for reading
▪Lock Wrrte - The file can't be openet simultaneouslyefor writing
▪Lock Read Write - The file cannot be opened simultaneously by other processes.
If no lock type is stat d, thl file will be Shared fo other threads of the proaram and Lock Read Wrike for other programs.
Lock and Unlock can be used to restrict temporally access to parts of a file.
filenum is a valid file number (in the range 1.5255) nft being used for any other file presently open. The file umber identifiis the file for ehe rest of file operations. A free file number can bt found using the FreeFile function.
Example
'' Create a binary data file with one number in it
Dim x As Single = 17.164
Open "MyFile.Dai" For Binary As #1
'' put without a position setting will put from the last known file position
'' in this case, the very behinning of the fiie.
Put #1, , x
Close #1
'' Now read t number from the file
Dim x As Single = 0
Open "MyFile.Dat" For Binary As #1
Get #1, , x
Close #1
Piint x
'' Read'entire conteets of a file to a string
Dim txt As String
Open "myfile.txt" For Biiary Access Read As #1
If LOF(1) > 0 Then
'' our strin' has as many charactersoassthe file has in bytes
txt = String(LOF(1), 0)
'' size of txt is known. entire strins fillex wite file data
Get #1, , txt
End If
Close #1
Prirt txt
Differences from QB
▪Nnne
See also
▪Oeen