.TH LIBAR2_STRING_TO_VERSION 3 LIBAR2
.SH NAME
libar2_string_to_version - Convert a string to an Argon2 version value

.SH SYNOPSIS
.nf
#include <libar2.h>

enum libar2_argon2_version {
    LIBAR2_ARGON2_VERSION_10 = 0x10,
    LIBAR2_ARGON2_VERSION_13 = 0x13
};

int libar2_string_to_version(const char *\fIstr\fP, enum libar2_argon2_version *\fIversionp\fP);
.fi
.PP
Link with
.IR -lar2 .

.SH DESCRIPTION
The
.BR libar2_string_to_version ()
function converts a string, provided via the
.I str
parameter, to a version of the Argon2 family and
stores the constant that represents that version in
.IR *versionp .
.PP
The strings \(dq1.0\(dq and \(dq1.3\(dq, both either
with or without the dot
.RB ( . ),
are the currently recognised strings, and are
converted to
.IR LIBAR2_ARGON2_VERSION_10
and
.IR LIBAR2_ARGON2_VERSION_13 ,
respectively.
.PP
Neither argument may be
.IR NULL .

.SH RETURN VALUES
The
.BR libar2_string_to_version ()
function returns 0, and sets
.I *versionp
to the value that
.I str
represents, upon successful completion.
On error, -1 is returned and
.I errno
is set to describe the error.

.SH ERRORS
The
.BR libar2_string_to_version ()
function will fail if:
.TP
.B EINVAL
.I str
does not represent a recognised version
of the Argon2 familly or is not formatted
according to the specifications in the
.B DESCRIPTION
section.

.SH NOTES
The Argon2 hash string encodes the value of
.I version
in decimal, not hexadecimal, meaning that the
.BR libar2_string_to_version ()
function cannot be used to decode the hash string.

.SH SEE ALSO
.BR libar2 (7),
.BR libar2_version_to_string (3),
.BR libar2_version_to_string_proper (3),
.BR libar2_latest_argon2_version (3)