FTELL(3)                   POSIX Programmer's Manual                  FTELL(3)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

NAME
       ftell, ftello -- return a file offset in a stream

SYNOPSIS
       #include <stdio.h>

       long ftell(FILE *stream);
       off_t ftello(FILE *stream);

DESCRIPTION
       The functionality described on this reference page is aligned with the
       ISO C standard. Any conflict between the requirements described here
       and the ISO C standard is unintentional. This volume of POSIX.1-2017
       defers to the ISO C standard.

       The ftell() function shall obtain the current value of the file-
       position indicator for the stream pointed to by stream.

       The ftell() function shall not change the setting of errno if
       successful.

       The ftello() function shall be equivalent to ftell(), except that the
       return value is of type off_t and the ftello() function may change the
       setting of errno if successful.

RETURN VALUE
       Upon successful completion, ftell() and ftello() shall return the
       current value of the file-position indicator for the stream measured in
       bytes from the beginning of the file.

       Otherwise, ftell() and ftello() shall return -1, and set errno to
       indicate the error.

ERRORS
       The ftell() and ftello() functions shall fail if:

       EBADF  The file descriptor underlying stream is not an open file
              descriptor.

       EOVERFLOW
              For ftell(), the current file offset cannot be represented
              correctly in an object of type long.

       EOVERFLOW
              For ftello(), the current file offset cannot be represented
              correctly in an object of type off_t.

       ESPIPE The file descriptor underlying stream is associated with a pipe,
              FIFO, or socket.

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       Section 2.5, Standard I/O Streams, fgetpos(), fopen(), fseek(), lseek()

       The Base Definitions volume of POSIX.1-2017, <stdio.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  In the event of any discrepancy between this version and the
       original IEEE and The Open Group Standard, the original IEEE and The
       Open Group Standard is the referee document. The original Standard can
       be obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017                             FTELL(3)
