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FSEEK
— Low level file positioning subroutineSEEK_SET
,
if set to 1, OFFSET is taken to be relative to the current position
SEEK_CUR
, and if set to 2 relative to the end of the file SEEK_END
.
On error, STATUS is set to a nonzero value. If STATUS the seek
fails silently.
This intrinsic routine is not fully backwards compatible with g77.
In g77, the FSEEK
takes a statement label instead of a
STATUS variable. If FSEEK is used in old code, change
CALL FSEEK(UNIT, OFFSET, WHENCE, *label)
to
INTEGER :: status CALL FSEEK(UNIT, OFFSET, WHENCE, status) IF (status /= 0) GOTO label
Please note that GNU Fortran provides the Fortran 2003 Stream facility.
Programmers should consider the use of new stream IO feature in new code
for future portability. See also Fortran 2003 status.
CALL FSEEK(UNIT, OFFSET, WHENCE[, STATUS])
UNIT | Shall be a scalar of type INTEGER .
|
OFFSET | Shall be a scalar of type INTEGER .
|
WHENCE | Shall be a scalar of type INTEGER .
Its value shall be either 0, 1 or 2.
|
STATUS | (Optional) shall be a scalar of type
INTEGER(4) .
|
PROGRAM test_fseek INTEGER, PARAMETER :: SEEK_SET = 0, SEEK_CUR = 1, SEEK_END = 2 INTEGER :: fd, offset, ierr ierr = 0 offset = 5 fd = 10 OPEN(UNIT=fd, FILE="fseek.test") CALL FSEEK(fd, offset, SEEK_SET, ierr) ! move to OFFSET print *, FTELL(fd), ierr CALL FSEEK(fd, 0, SEEK_END, ierr) ! move to end print *, FTELL(fd), ierr CALL FSEEK(fd, 0, SEEK_SET, ierr) ! move to beginning print *, FTELL(fd), ierr CLOSE(UNIT=fd) END PROGRAM