NAME

       fseeko, ftello - seek to or report file position

SYNOPSIS

       #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

       The fseeko() and ftello() functions are identical to fseek(3) and ftell(3) (see fseek(3)),
       respectively, except that the offset argument of fseeko() and the return value of ftello()
       is of type off_t instead of long.

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

RETURN VALUE

       On  successful  completion, fseeko() returns 0, while ftello() returns the current offset.
       Otherwise, -1 is returned and errno is set to indicate the error.

ERRORS

       See the ERRORS in fseek(3).

VERSIONS

       These functions are available under glibc since version 2.1.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       ┌───────────────────────────────────────────────────────────────┬───────────────┬─────────┐
       │Interface                                                      │ Attribute     │ Value   │
       ├───────────────────────────────────────────────────────────────┼───────────────┼─────────┤
       │fseeko(), ftello()                                             │ Thread safety │ MT-Safe │
       └───────────────────────────────────────────────────────────────┴───────────────┴─────────┘

CONFORMING TO

       POSIX.1-2001, POSIX.1-2008, SUSv2.

NOTES

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

SEE ALSO

       fseek(3)

COLOPHON

       This  page  is  part of release 5.13 of the Linux man-pages project.  A description of the
       project, information about reporting bugs, and the latest version of  this  page,  can  be
       found at https://www.kernel.org/doc/man-pages/.

                                            2021-03-22                                  FSEEKO(3)