FSEEK

Portability Function: Repositions a file specified by a Fortran external unit.

Module

USE IFPORT

result = FSEEK (lunit,offset,from)

lunit

(Input) INTEGER(4). External unit number of a file.

offset

(Input) INTEGER(4) or INTEGER(8). Offset in bytes, relative to from, that is to be the new location of the file marker.

from

(Input) INTEGER(4). A position in the file. It must be one of the following:

Value	Variable	Position
0	SEEK_SET	Positions the file relative to the beginning of the file.
1	SEEK_CUR	Positions the file relative to the current position.
2	SEEK_END	Positions the file relative to the end of the file.

Results

The result type is INTEGER(4). The result is zero if the repositioning was successful; otherwise, an error code, such as:

EINVAL: The specified unit is invalid (either not already open, or an invalid unit number), or the from parameter is invalid.

The file specified in lunit must be open.

Example

USE IFPORT
integer(4) istat, offset, ipos
character ichar
OPEN (unit=1,file='datfile.dat')
offset = 5
ipos = 0
istat=fseek(1,offset,ipos)
if (.NOT. stat) then
  istat=fgetc(1,ichar)
  print *, 'data is ',ichar
end if