Originální popis anglicky:
fgetc - get a byte from a stream
Návod, kniha: POSIX Programmer's Manual
#include <stdio.h>
int fgetc(FILE *
stream);
If the end-of-file indicator for the input stream pointed to by
stream is
not set and a next byte is present, the
fgetc() function shall obtain
the next byte as an
unsigned char converted to an
int,
from the input stream pointed to by
stream, and advance the associated
file position indicator for the stream (if defined). Since
fgetc()
operates on bytes, reading a character consisting of multiple bytes (or
"a multi-byte character") may require multiple calls to
fgetc().
The
fgetc() function may mark the
st_atime field of the file
associated with
stream for update. The
st_atime field shall be
marked for update by the first successful execution of
fgetc(),
fgets(),
fgetwc(),
fgetws(),
fread(),
fscanf(),
getc(),
getchar(),
gets(), or
scanf() using
stream that returns data not supplied by a prior
call to
ungetc() or
ungetwc().
Upon successful completion,
fgetc() shall return the next byte from the
input stream pointed to by
stream. If the end-of-file indicator for the
stream is set, or if the stream is at end-of-file, the end-of-file indicator
for the stream shall be set and
fgetc() shall return EOF. If a read
error occurs, the error indicator for the stream shall be set,
fgetc()
shall return EOF, and shall set
errno to indicate the error.
The
fgetc() function shall fail if data needs to be read and:
- EAGAIN
- The O_NONBLOCK flag is set for the file descriptor
underlying stream and the process would be delayed in the
fgetc() operation.
- EBADF
- The file descriptor underlying stream is not a valid
file descriptor open for reading.
- EINTR
- The read operation was terminated due to the receipt of a
signal, and no data was transferred.
- EIO
- A physical I/O error has occurred, or the process is in a
background process group attempting to read from its controlling terminal,
and either the process is ignoring or blocking the SIGTTIN signal or the
process group is orphaned. This error may also be generated for
implementation-defined reasons.
- EOVERFLOW
- The file is a regular file and an attempt was made to read
at or beyond the offset maximum associated with the corresponding stream.
The
fgetc() function may fail if:
- ENOMEM
- Insufficient storage space is available.
- ENXIO
- A request was made of a nonexistent device, or the request
was outside the capabilities of the device.
The following sections are informative.
None.
If the integer value returned by
fgetc() is stored into a variable of
type
char and then compared against the integer constant EOF, the
comparison may never succeed, because sign-extension of a variable of type
char on widening to integer is implementation-defined.
The
ferror() or
feof() functions must be used to distinguish
between an error condition and an end-of-file condition.
None.
None.
feof() ,
ferror() ,
fopen() ,
getchar() ,
getc() , the Base Definitions volume of
IEEE Std 1003.1-2001,
<stdio.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 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
.
