This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface

       If the integer value returned by getc() 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.

       Since it may be implemented as a macro, getc() may treat incorrectly a stream argument with side-effects.
       In particular, getc(*f++) does not necessarily work as expected. Therefore, use of this  function  should
       be preceded by "#undefgetc" in such situations; fgetc() could also be used.

       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                                          GETC(3POSIX)

       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  getc()  function  shall be equivalent to fgetc(), except that if it is implemented as a macro it may
       evaluate stream more than once, so the argument should never be an expression with side-effects.

       Refer to fgetc().

       Thefollowingsectionsareinformative.

       None.

       None.

       getc — get a byte from a stream

       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.

       None.

       Refer to fgetc().

Section2.5, StandardI/OStreams, fgetc()

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

       #include <stdio.h>

       int getc(FILE *stream);