FGETC(3P)                   POSIX Programmer's Manual                  FGETC(3P)

       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.

       fgetc - get a byte from a stream

       #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.

              The file is a regular file and an attempt was made to read at or
              beyond the offset maximum associated with the corresponding

       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.


       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.



       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 .

IEEE/The Open Group                   2003                             FGETC(3P)