NAME

       fgetc - get a byte from a stream

SYNOPSIS

       #include <stdio.h>

       int fgetc(FILE *stream);

DESCRIPTION

       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().

RETURN VALUE

       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.

ERRORS

       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.

EXAMPLES

       None.

APPLICATION USAGE

       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.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       feof()  ,  ferror()  ,  fopen()  ,  getchar()  ,  getc()  , the Base Definitions volume of
       IEEE Std 1003.1-2001, <stdio.h>

COPYRIGHT

       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 .