1.\" Copyright (c) 1990, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" Chris Torek and the American National Standards Committee X3, 6.\" on Information Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)putc.3 8.1 (Berkeley) 6/4/93 33.\" 34.Dd January 23, 2020 35.Dt PUTC 3 36.Os 37.Sh NAME 38.Nm fputc , 39.Nm fputc_unlocked , 40.Nm putc , 41.Nm putc_unlocked , 42.Nm putchar , 43.Nm putchar_unlocked , 44.Nm putw 45.Nd output a character or word to a stream 46.Sh LIBRARY 47.Lb libc 48.Sh SYNOPSIS 49.In stdio.h 50.Ft int 51.Fn fputc "int c" "FILE *stream" 52.Ft int 53.Fn fputc_unlocked "int c" "FILE *stream" 54.Ft int 55.Fn putc "int c" "FILE *stream" 56.Ft int 57.Fn putc_unlocked "int c" "FILE *stream" 58.Ft int 59.Fn putchar "int c" 60.Ft int 61.Fn putchar_unlocked "int c" 62.Ft int 63.Fn putw "int w" "FILE *stream" 64.Sh DESCRIPTION 65The 66.Fn fputc 67function 68writes the character 69.Fa c 70(converted to an ``unsigned char'') 71to the output stream pointed to by 72.Fa stream . 73.Pp 74The 75.Fn putc 76macro acts essentially identically to 77.Fn fputc , 78but is a macro that expands in-line. 79It may evaluate 80.Fa stream 81more than once, so arguments given to 82.Fn putc 83should not be expressions with potential side effects. 84.Pp 85The 86.Fn putchar 87function 88is identical to 89.Fn putc 90with an output stream of 91.Dv stdout . 92.Pp 93The 94.Fn putw 95function 96writes the specified 97.Vt int 98to the named output 99.Fa stream . 100.Pp 101The 102.Fn fputc_unlocked , 103.Fn putc_unlocked , 104and 105.Fn putchar_unlocked 106functions are equivalent to 107.Fn fputc , 108.Fn putc , 109and 110.Fn putchar 111respectively, 112except that the caller is responsible for locking the stream 113with 114.Xr flockfile 3 115before calling them. 116These functions may be used to avoid the overhead of locking the stream 117for each character, and to avoid output being interspersed from multiple 118threads writing to the same stream. 119.Sh RETURN VALUES 120The functions, 121.Fn fputc , 122.Fn putc , 123.Fn putchar , 124.Fn putc_unlocked 125and 126.Fn putchar_unlocked 127return the character written. 128If an error occurs, the value 129.Dv EOF 130is returned. 131The 132.Fn putw 133function 134returns 0 on success; 135.Dv EOF 136is returned if 137a write error occurs, 138or if an attempt is made to write a read-only stream. 139.Sh SEE ALSO 140.Xr ferror 3 , 141.Xr flockfile 3 , 142.Xr fopen 3 , 143.Xr getc 3 , 144.Xr putwc 3 , 145.Xr stdio 3 146.Sh STANDARDS 147The functions 148.Fn fputc , 149.Fn putc , 150and 151.Fn putchar , 152conform to 153.St -isoC . 154The 155.Fn putc_unlocked 156and 157.Fn putchar_unlocked 158functions conform to 159.St -p1003.1-2001 . 160A function 161.Fn putw 162function appeared in 163.At v6 . 164.Sh BUGS 165The size and byte order of an 166.Vt int 167varies from one machine to another, and 168.Fn putw 169is not recommended for portable applications. 170