minix/lib/libc/stdio/putc.3

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.\"     @(#)putc.3	8.1 (Berkeley) 6/4/93
.\"
.Dd May 6, 2010
.Dt PUTC 3
.Os
.Sh NAME
.Nm fputc ,
.Nm putc ,
.Nm putchar ,
.Nm putc_unlocked ,
.Nm putchar_unlocked ,
.Nm putw
.Nd output a character or word to a stream
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In stdio.h
.Ft int
.Fn fputc "int c" "FILE *stream"
.Ft int
.Fn putc "int c" "FILE *stream"
.Ft int
.Fn putchar "int c"
.Ft int
.Fn putc_unlocked "int c" "FILE *stream"
.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 .
.Pp
.Fn putc
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.
.Pp
.Fn putchar
is identical to
.Fn putc
with an output stream of
.Em stdout .
.Pp
The
.Fn putc_unlocked
and
.Fn putchar_unlocked
functions provide functionality identical to that of
.Fn putc
and
.Fn putchar ,
respectively, but do not perform implicit locking of the streams they
operate on.
In multi-threaded programs they may be used
.Em only
within a scope in which the stream
has been successfully locked by the calling thread using either
.Xr flockfile 3
or
.Xr ftrylockfile 3 ,
and may later be released using
.Xr funlockfile 3 .
.Pp
The
.Fn putw
function
writes the specified
.Em int
to the named output
.Fa stream .
.Sh RETURN VALUES
The functions,
.Fn fputc ,
.Fn putc
and
.Fn putchar
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 fopen 3 ,
.Xr getc 3 ,
.Xr stdio 3
.Sh STANDARDS
The functions
.Fn fputc ,
.Fn putc ,
and
.Fn putchar ,
conform to
.St -ansiC .
The functions
.Fn putc_unlocked
and
.Fn putchar_unlocked
conform to
.St -p1003.1-96 .
.Sh HISTORY
The functions
.Fn putc ,
.Fn putchar ,
and
.Fn putw
first appeared in
.At v6 .
The function
.Fn fputc
appeared in
.At v7 .
.Sh BUGS
The size and byte order of an
.Em int
varies from one machine to another, and
.Fn putw
is not recommended for portable applications.