.TH LIBKECCAK_UNHEX 3 LIBKECCAK-%VERSION%
.SH NAME
libkeccak_unhex - Converts a hexadecimal hashsum to binary
.SH SYNOPSIS
.LP
.nf
#include <libkeccak.h>
.P
void libkeccak_unhex(char *restrict \fIoutput\fP,
                     const char *restrict \fIhashsum\fP);
.fi
.P
Link with \fI-lkeccak\fP.
.SH DESCRIPTION
The
.BR libkeccak_unhex ()
function
converts a hexadecimal hashsum, stored in \fIhashsum\fP,
to binary, and stores the binary representation in
\fIoutput\fP.
.PP
\fIhashsum\fP must be terminated by a NUL-character.
It may be in either lowercase or uppercase, or a mixture
thereof. \fIoutput\fP will not be terminated.
.PP
(\fBstrlen\fP(\fIhashsum\fP) / 2) bytes will be written to
the beginning of \fIoutput\fP. It should therefore have
an allocation of at least that number of bytes.
.SH RETURN VALUES
The
.BR libkeccak_unhex ()
function does return any value.
.SH ERRORS
The
.BR libkeccak_unhex ()
function cannot fail.
.SH NOTES
\fIhashsum\fP must have an even number of digits
(characters excluding the terminating NUL-character.)
.SH SEE ALSO
.BR libkeccak_behex_lower (3),
.BR libkeccak_behex_upper (3)
.SH AUTHORS
Principal author, Mattias Andrée.  See the LICENSE file for the full
list of authors.
.SH BUGS
Please report bugs to https://github.com/maandree/libkeccak/issues or to
maandree@kth.se