---
name: "oath_hex2bin"
section: "3"
platform: "linux"
package: "oath-toolkit"
version: "2.6.15-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/oath_hex2bin"
---

# oath\_hex2bin(3)

API function

## NAME

oath\_hex2bin - API function

## SYNOPSIS

**#include \<oath.h\>**

**int oath\_hex2bin(const char \*** *hexstr***, char \*** *binstr***, size\_t \*** *binlen***);**

## ARGUMENTS

- const char \* hexstr

  input string with hex data

- char \* binstr

  output string that holds binary data, or NULL

- size\_t \* binlen

  output variable holding needed length of *binstr*

## DESCRIPTION

Convert string with hex data to binary data.

Non-hexadecimal data are not ignored but instead will lead to an **OATH\_INVALID\_HEX** error.

If *binstr* is NULL, then *binlen* will be populated with the necessary length.  If the *binstr* buffer is too small, **OATH\_TOO\_SMALL\_BUFFER** is returned and *binlen* will contain the necessary length.

## RETURNS

On success, **OATH\_OK** (zero) is returned, otherwise an error code is returned.

## REPORTING BUGS

Report bugs to \<oath-toolkit-help@nongnu.org\>. liboath home page: https://oath-toolkit.codeberg.page/ General help using GNU software: http://www.gnu.org/gethelp/

## COPYRIGHT

Copyright © 2009-2026 Simon Josefsson.\
 Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved.