вернуть смещение файла в потоке (return a file offset in a stream)
Пролог (Prolog)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
Имя (Name)
ftell, ftello — return a file offset in a stream
Синопсис (Synopsis)
#include <stdio.h>
long ftell(FILE *stream);
off_t ftello(FILE *stream);
Описание (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.
Возвращаемое значение (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.
Ошибки (Error)
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.
Примеры (Examples)
None.
Использование в приложениях (Application usage)
None.
Обоснование (Rationale)
None.
Будущие направления (Future directions)
None.
Смотри также (See also)
Section 2.5, Standard I/O Streams, fgetpos(3p), fopen(3p),
fseek(3p), lseek(3p)
The Base Definitions volume of POSIX.1‐2017, stdio.h(0p)
