1FSEEK(3)                   Linux Programmer's Manual                  FSEEK(3)
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NAME

6       fgetpos, fseek, fsetpos, ftell, rewind - reposition a stream
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SYNOPSIS

9       #include <stdio.h>
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11       int fseek(FILE *stream, long offset, int whence);
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13       long ftell(FILE *stream);
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15       void rewind(FILE *stream);
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17       int fgetpos(FILE *stream, fpos_t *pos);
18       int fsetpos(FILE *stream, fpos_t *pos);
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DESCRIPTION

21       The  fseek()  function  sets the file position indicator for the stream
22       pointed to by stream.  The new position, measured in bytes, is obtained
23       by  adding offset bytes to the position specified by whence.  If whence
24       is set to SEEK_SET, SEEK_CUR, or SEEK_END, the offset  is  relative  to
25       the  start of the file, the current position indicator, or end-of-file,
26       respectively.  A successful call to the  fseek()  function  clears  the
27       end-of-file  indicator  for  the  stream  and undoes any effects of the
28       ungetc(3) function on the same stream.
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30       The ftell() function obtains the current value  of  the  file  position
31       indicator for the stream pointed to by stream.
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33       The  rewind()  function sets the file position indicator for the stream
34       pointed to by stream to the beginning of the file.   It  is  equivalent
35       to:
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37              (void) fseek(stream, 0L, SEEK_SET)
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39       except  that  the  error  indicator for the stream is also cleared (see
40       clearerr(3)).
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42       The fgetpos() and fsetpos() functions are alternate interfaces  equiva‐
43       lent  to ftell() and fseek() (with whence set to SEEK_SET), setting and
44       storing the current value of the file offset into or  from  the  object
45       referenced  by pos.  On some non-Unix systems an fpos_t object may be a
46       complex object and these routines may be the only way to portably repo‐
47       sition a text stream.
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RETURN VALUE

50       The  rewind()  function  returns no value.  Upon successful completion,
51       fgetpos(), fseek(), fsetpos() return 0, and ftell() returns the current
52       offset.   Otherwise,  -1  is  returned and errno is set to indicate the
53       error.
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ERRORS

56       EBADF  The stream specified is not a seekable stream.
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58       EINVAL The whence argument to fseek() was not  SEEK_SET,  SEEK_END,  or
59              SEEK_CUR.
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61       The  functions fgetpos(), fseek(), fsetpos(), and ftell() may also fail
62       and set errno  for  any  of  the  errors  specified  for  the  routines
63       fflush(3), fstat(2), lseek(2), and malloc(3).
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CONFORMING TO

66       C89, C99.
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SEE ALSO

69       lseek(2), fseeko(3)
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COLOPHON

72       This  page  is  part of release 3.22 of the Linux man-pages project.  A
73       description of the project, and information about reporting  bugs,  can
74       be found at http://www.kernel.org/doc/man-pages/.
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78GNU                               1993-11-29                          FSEEK(3)
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