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Three functions are available for setting and determining the position of the file pointer for a given file.
Return the position of the file pointer as the number of characters from the beginning of the file specified by file descriptor fid.
Set the file pointer to the location offset within the file fid.
The pointer is positioned offset characters from the origin, which
may be one of the predefined variables SEEK_SET
(beginning),
SEEK_CUR
(current position), or SEEK_END
(end of file)
or strings "bof"
, "cof"
, or
"eof"
. If origin is omitted, SEEK_SET
is
assumed. offset may be positive, negative, or zero but not all
combinations of origin and offset can be realized.
fseek
returns 0 on success and -1 on error.
See also: fskipl, frewind, ftell, fopen, SEEK_SET, SEEK_CUR, SEEK_END.
Return the numerical value to pass to fseek
to position the file pointer
relative to the beginning of the file.
Return the numerical value to pass to fseek
to position the file pointer
relative to the current position.
Return the numerical value to pass to fseek
to position the file pointer
relative to the end of the file.
Move the file pointer to the beginning of the file specified by file descriptor fid.
frewind
returns 0 for success, and -1 if an error is encountered. It
is equivalent to fseek (fid, 0, SEEK_SET)
.
The following example stores the current file position in the variable
marker
, moves the pointer to the beginning of the file, reads
four characters, and then returns to the original position.
marker = ftell (myfile); frewind (myfile); fourch = fgets (myfile, 4); fseek (myfile, marker, SEEK_SET);
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