Moves the file pointer to the specified position in a file of any size. The file pointer is the position in the file at which the next read or write begins.
FileSeek64 ( file#, position, origin )
Argument |
Description |
|---|---|
file# |
The integer assigned to the file when it was opened. |
position |
A long whose value is the new position of the file pointer relative to the position specified in origin, in bytes. |
origin |
The value of the SeekType enumerated datatype specifying where you want to start the seek. Values are:
|
Longlong. Returns the file position after the seek operation has been performed. If any argument’s value is null, FileSeek64 returns null.
Use FileSeek64 to move within a binary file that you have opened in stream mode. FileSeek64 positions the file pointer so that the next FileReadEx or FileWriteEx occurs at that position within the file.
If origin is set to FromBeginning!, and
the file is not opened in stream mode, the byte-order mark is ignored
automatically. For example, suppose the file’s hexadecimal
display is FF FE 54 00 68 00 69 00 73 00,
the following example illustrates the behavior:
long ll_pos // after the following statement, the file pointer is // at 68, not 54, and ll_pos = 2, not 4 ll_pos = FileSeek64( filenum, 2, FromBeginning!) // ll_pos = 2, not 4 ll_pos = FileSeek64( filenum, 0, FromCurrent!) // ll_pos = 2, not 4 ll_pos = FileSeek64( filenum, -6, FromEnd!)
This example positions the file pointer 14 bytes from the end of the file:
integer li_FileNum
li_FileNum = FileOpen("emp_data")
FileSeek64(li_FileNum, -14, FromEnd!)
This example moves the file pointer from its current position 14 bytes toward the end of the file. In this case, if no processing has occurred after FileOpen to affect the file pointer, specifying FromCurrent! is the same as specifying FromBeginning!:
integer li_FileNum
li_FileNum = FileOpen("emp_data")
FileSeek64(li_FileNum, 14, FromCurrent!)
