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