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.

NAME

       getc — get a byte from a stream

SYNOPSIS

       #include <stdio.h>

       int getc(FILE *stream);

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  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.

RETURN VALUE

       Refer to fgetc().

ERRORS

       Refer to fgetc().

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       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.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       Section 2.5, Standard I/O Streams, fgetc()

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

COPYRIGHT

       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 .