libutf8_encode.3


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.TH LIBUTF8_ENCODE 3 LIBUTF8
.SH NAME
libutf8_encode - Encode a codepoint as UTF-8

.SH SYNOPSIS
.nf
#include <libutf8.h>

size_t \fBlibutf8_encode\fP(char *\fIout_buffer\fP, uint_least32_t \fIcodepoint\fP);
.fi
.PP
Link with
.IR -lutf8 .

.SH DESCRIPTION
The
.BR libutf8_encode ()
function encodes
.I codepoint
as UTF-8 in
.IR Iout_buffer .
The buffer must have room for the number of bytes returned, up to six bytes
for all accept values of
.I codepoint
and up to four bytes for all codepoints valid within the Unicode standard.
.PP
The output is not NUL-terminated.

.SH RETURN VALUE
The
.BR libutf8_encode ()
function returns the number of bytes written, or zero if
.I codepoint
is unrepresentable.

.SH ERRORS
The
.BR libutf8_encode ()
function cannot fail per se, and never sets
.IR errno ;
.B EDOM
is an appropriate value when the function returns zero.

.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.PP
.TS
allbox;
lb lb lb lb
l l l l.
Interface	Thread safety	Async-signal safety	Async-cancel safety
T{
.BR libutf8_encode ()
T}	MT-Safe	AS-Safe	AC-Safe
.TE
.sp

.SH NOTES
UTF-8 has historically supported 31-bit codepoints. The
.BR libutf8_encode ()
function does so as well, and follows regulare pattern, extended,
as it was historically, to support 31-bit integers using up to
6 bytes. Thus the function supports codepoints beyond 
.BR LIBUTF8_ULTIMATE_CODEPOINT .

.SH SEE ALSO
.BR libutf8 (7),
.BR libutf8_encode_measure (3),
.BR libutf8_decode (3)