fseek---set file position
#include <stdio.h> int fseek(FILE *fp, long offset, int whence)
Objects of type
FILE can have a "position" that records how much
of the file your program has already read. Many of the
depend on this position, and many change it as a side effect.
You can use
fseek to set the position for the file identified by
fp. The value of offset determines the new position, in one
of three ways selected by the value of whence (defined as macros
SEEK_SET---offset is the absolute file position (an offset
from the beginning of the file) desired. offset must be positive.
SEEK_CUR---offset is relative to the current file position.
offset can meaningfully be either positive or negative.
SEEK_END---offset is relative to the current end of file.
offset can meaningfully be either positive (to increase the size
of the file) or negative.
ftell to determine the current file position.
0 when successful. If
fseek fails, the
EOF. The reason for failure is indicated in
ESPIPE (the stream identified by fp doesn't support
EINVAL (invalid file position).
ANSI C requires
Supporting OS subroutines required:
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