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@(#)putc.3 8.1 (Berkeley) 6/4/93
$FreeBSD: stable/11/lib/libc/stdio/putc.3 357852 2020-02-13 03:13:29Z kevans $
.Dd January 23, 2020 .Dt PUTC 3 .Os .Sh NAME .Nm fputc , .Nm fputc_unlocked , .Nm putc , .Nm putc_unlocked , .Nm putchar , .Nm putchar_unlocked , .Nm putw .Nd output a character or word to a stream .Sh LIBRARY .Lb libc .Sh SYNOPSIS n stdio.h .Ft int .Fn fputc "int c" "FILE *stream" .Ft int .Fn fputc_unlocked "int c" "FILE *stream" .Ft int .Fn putc "int c" "FILE *stream" .Ft int .Fn putc_unlocked "int c" "FILE *stream" .Ft int .Fn putchar "int c" .Ft int .Fn putchar_unlocked "int c" .Ft int .Fn putw "int w" "FILE *stream" .Sh DESCRIPTION The .Fn fputc function writes the character .Fa c (converted to an ``unsigned char'') to the output stream pointed to by .Fa stream .
p The .Fn putc macro acts essentially identically to .Fn fputc , but is a macro that expands in-line. It may evaluate .Fa stream more than once, so arguments given to .Fn putc should not be expressions with potential side effects.
p The .Fn putchar function is identical to .Fn putc with an output stream of .Dv stdout .
p The .Fn putw function writes the specified .Vt int to the named output .Fa stream .
p The .Fn fputc_unlocked , .Fn putc_unlocked , and .Fn putchar_unlocked functions are equivalent to .Fn fputc , .Fn putc , and .Fn putchar respectively, except that the caller is responsible for locking the stream with .Xr flockfile 3 before calling them. These functions may be used to avoid the overhead of locking the stream for each character, and to avoid output being interspersed from multiple threads writing to the same stream. .Sh RETURN VALUES The functions, .Fn fputc , .Fn putc , .Fn putchar , .Fn putc_unlocked and .Fn putchar_unlocked return the character written. If an error occurs, the value .Dv EOF is returned. The .Fn putw function returns 0 on success; .Dv EOF is returned if a write error occurs, or if an attempt is made to write a read-only stream. .Sh SEE ALSO .Xr ferror 3 , .Xr flockfile 3 , .Xr fopen 3 , .Xr getc 3 , .Xr putwc 3 , .Xr stdio 3 .Sh STANDARDS The functions .Fn fputc , .Fn putc , and .Fn putchar , conform to .St -isoC . The .Fn putc_unlocked and .Fn putchar_unlocked functions conform to .St -p1003.1-2001 . A function .Fn putw function appeared in .At v6 . .Sh BUGS The size and byte order of an .Vt int varies from one machine to another, and .Fn putw is not recommended for portable applications.