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.

      // 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

• FCREATE()
• FERROR()
• FOPEN()
• FREAD()
• FREADSTR()
• FWRITE()