FSEEK()
Positions the file pointer in a file.
- Syntax
-
- FSEEK( <nHandle>, <nOffset>, [<nOrigin>] ) --> nPosition
- Arguments
-
- <nHandle> DOS file handle.
- <nOffset> The number of bytes to move.
- <nOrigin> The relative position in the file.
- Returns
-
- <nPosition> the current position relative to begin-of-file
- Description
-
- This function sets the file pointer in the file whose DOS file handle is <nHandle> and moves the file pointer by <expN2> bytes from the file position designated by <nOrigin>. The returned value is the relative position of the file pointer to the beginning-of-file marker once the operation has been completed.
- <nHandle> is the file handle number. It is obtained from the FOPEN() or FCREATE() function.
- The value of <nOffSet> is the number of bytes to move the file pointer from the position determined by <nOrigin>.The value of <nOffset> may be a negative number, suggesting backward movement.
- The value of <nOrigin> designates the starting point from which the file pointer should he moved, as shown in the following table:
<nOrigin> | fileio.ch | File position |
|
0 | FS_SET | Beginning of file |
1 | FS_RELATIVE | Current file pointer position |
2 | FS_END | End of file |
- If a value is not provided for <nOrigin>, it defaults to 0 and moves the file pointer from the beginning of the file.
Examples
// here is a function that read one text line from an open file
// nH = file handle obtained from FOPEN()
// cB = a string buffer passed-by-reference to hold the result
// nMaxLine = maximum number of bytes to read
#define EOL HB_OSNEWLINE()
FUNCTION FREADln( nH, cB, nMaxLine )
LOCAL cLine, nSavePos, nEol, nNumRead
cLine := space( nMaxLine )
cB := ''
nSavePos := FSEEK( nH, 0, FS_RELATIVE )
nNumRead := FREAD( nH, @cLine, nMaxLine )
IF ( nEol := AT( EOL, substr( cLine, 1, nNumRead ) ) ) == 0
cB := cLine
ELSE
cB := SUBSTR( cLine, 1, nEol - 1 )
FSEEK( nH, nSavePos + nEol + 1, FS_SET )
ENDIF
RETURN nNumRead != 0
- Status
- Ready
- Compliance
-
- This function is CA-Clipper compliant.
- Files
-
- Library is rtl Header is fileio.ch
- See Also