NAME

putc — put a byte on a stream

SYNOPSIS

#include <stdio.h>

int putc(int c, FILE *stream);


DESCRIPTION

^[CX] 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.1-2024 defers to the ISO C standard.

The putc() function shall be equivalent to fputc(), 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 fputc.

ERRORS

Refer to fputc.

EXAMPLES

None.

APPLICATION USAGE

Since it may be implemented as a macro, putc() may treat a stream argument with side-effects incorrectly. In particular, putc(c,*f++) does not necessarily work correctly. Therefore, use of this function is not recommended in such situations; fputc() should be used instead.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

2.5 Standard I/O Streams, fputc

XBD <stdio.h>

CHANGE HISTORY

First released in Issue 1. Derived from Issue 1 of the SVID.

Issue 7

POSIX.1-2008, Technical Corrigendum 1, XSH/TC1-2008/0470 [14] is applied.