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<< Click to Display Table of Contents >> Open (statement) |
Open FileName [For Mode] [Access AccessMode] As [#]FileNumber
Opens a file for input/output operations.
FileName is the name of the file.
The optional parameter Mode can take one of the following values:
Mode |
Description |
Input |
Sequential input. The file must already exist. AccessMode, if given, must be set to Read. |
Output |
Sequential output. The file is automatically created for output. If a file with the given name already exists, the file will be overwritten. AccessMode, if given, must be set to Write. |
Append |
Sequential output. Identical to Output, however the file pointer will be set to the end of the file, so that all following output commands append data to the existing file. |
The optional parameter AccessMode restricts the type of access to the file:
AccessMode |
Description |
Read |
Opens the file only for reading. |
Write |
Opens the file only for writing. |
Read Write |
Opens the file for reading and writing. |
If the file does not exist, it will be automatically created, if either Append or Output mode was chosen; otherwise the Open command fails.
If the file is already opened by another process or the desired access mode is not possible, the Open command fails.
FileNumber is an integer value between 1 and 255 which identifies the file in the following access functions. The index of the next free file pointer can be returned using the FreeFile function.
Example:
Sub Main
Open "TESTFILE" For Output As #1 ' Create file
userData1$ = InputBox("Enter one text line.")
userData2$ = InputBox("Enter one more text line.")
Write #1, userData1, userData2 ' Write lile
Close #1
Open "TESTFILE" for Input As #2 ' Open file
Print "File contents:"
Do While Not EOF(2)
Line Input #2, FileData ' Read line
Print FileData
Loop
Close #2 ' Close file
Kill "TESTFILE" ' Delete file
End Sub