fgetpos.3s (2010 09)

fgetpos(3S) fgetpos(3S)

NAME

fgetpos( ), fsetpos( ) - save and restore a ﬁle position indicator for a stream

SYNOPSIS

#include <stdio.h>

int fgetpos(FILE *__restrict stream, fpos_t *__restrict pos);

int fsetpos(FILE *stream, const fpos_t *pos);

DESCRIPTION

fgetpos() Store the current value of the ﬁle position indicator for the stream pointed to by stream

in the object pointed to by pos. The value stored contains information usable by

fset-

pos() for repositioning the stream to its position at the time of the call to

fgetpos().

fsetpos() Set the ﬁle position indicator for the stream pointed to by stream according to the value

of the object pointed to by pos , which must be a value set by an earlier call to

fget-

pos() on the same stream.

A successful call to

fsetpos() clears the end-of-ﬁle indicator for the stream and

undoes any effects of ungetc(3S) on the same stream. After a

fsetpos() call, the next

operation on a update stream can be either input or output.

RETURN VALUE

If successful, these functions return zero; otherwise non-zero.

ERRORS

fgetpos() fails, errno is set to one of the following values.

[EINVAL] The current value of the ﬁle position cannot be represented correctly in an object of size

fpos_t in this environment.

Additional

errno values may be set by the underlying ftell() function (see fseek (3S)).

WARNINGS

Failure can occur if these functions are used on a ﬁle that has not been opened via

fopen(). In particu-

lar, they must not be used on a terminal or on a ﬁle opened via popen (3S).

fsetpos() has no effect on streams that are open for append (see fopen (3S)).