fseeko(3) - Linux manual page (original) (raw)

fseeko(3) Library Functions Manual fseeko(3)

NAME top

   fseeko, ftello - seek to or report file position

LIBRARY top

   Standard C library (_libc_, _-lc_)

SYNOPSIS top

   **#include <stdio.h>**

   **int fseeko(FILE ***_stream_**, off_t** _offset_**, int** _whence_**);**
   **off_t ftello(FILE ***_stream_**);**

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

   **fseeko**(), **ftello**():
       _FILE_OFFSET_BITS == 64 || _POSIX_C_SOURCE >= 200112L

DESCRIPTION top

   The **fseeko**() and **ftello**() functions are identical to [fseek(3)](../man3/fseek.3.html) and
   [ftell(3)](../man3/ftell.3.html) (see [fseek(3)](../man3/fseek.3.html)), respectively, except that the _offset_
   argument of **fseeko**() and the return value of **ftello**() is of type
   _offt_ instead of _long_.

   On some architectures, both _offt_ and _long_ are 32-bit types, but
   defining **_FILE_OFFSET_BITS** with the value 64 (before including _any_
   header files) will turn _offt_ into a 64-bit type.

RETURN VALUE top

   On successful completion, **fseeko**() returns 0, while **ftello**()
   returns the current offset.  Otherwise, -1 is returned and _[errno](../man3/errno.3.html)_
   is set to indicate the error.

ERRORS top

   See the ERRORS in [fseek(3)](../man3/fseek.3.html).

ATTRIBUTES top

   For an explanation of the terms used in this section, see
   [attributes(7)](../man7/attributes.7.html).
   ┌──────────────────────────────────────┬───────────────┬─────────┐
   │ **Interface** │ **Attribute** │ **Value** │
   ├──────────────────────────────────────┼───────────────┼─────────┤
   │ **fseeko**(), **ftello**()                   │ Thread safety │ MT-Safe │
   └──────────────────────────────────────┴───────────────┴─────────┘

STANDARDS top

   POSIX.1-2008.

HISTORY top

   glibc 2.1.  POSIX.1-2001, SUSv2.

NOTES top

   The declarations of these functions can also be obtained by
   defining the obsolete **_LARGEFILE_SOURCE** feature test macro.

SEE ALSO top

   [fseek(3)](../man3/fseek.3.html)

COLOPHON top

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Linux man-pages 6.10 2024-07-23 fseeko(3)

Pages that refer to this page:fseek(3), off_t(3type), open_memstream(3), feature_test_macros(7)