FIDO\_DEV\_OPEN(3) Library Functions Manual FIDO\_DEV\_OPEN(3) # [NAME](#NAME) `fido_dev_open`, `fido_dev_open_with_info`, `fido_dev_close`, `fido_dev_cancel`, `fido_dev_new`, `fido_dev_new_with_info`, `fido_dev_free`, `fido_dev_force_fido2`, `fido_dev_force_u2f`, `fido_dev_is_fido2`, `fido_dev_is_winhello`, `fido_dev_supports_credman`, `fido_dev_supports_cred_prot`, `fido_dev_supports_permissions`, `fido_dev_supports_pin`, `fido_dev_supports_uv`, `fido_dev_has_pin`, `fido_dev_has_uv`, `fido_dev_protocol`, `fido_dev_build`, `fido_dev_flags`, `fido_dev_major`, `fido_dev_minor` — FIDO2 device open/close and related functions # [SYNOPSIS](#SYNOPSIS) `#include ` `int` `fido_dev_open`(`fido_dev_t *dev`, `const char *path`); `int` `fido_dev_open_with_info`(`fido_dev_t *dev`); `int` `fido_dev_close`(`fido_dev_t *dev`); `int` `fido_dev_cancel`(`fido_dev_t *dev`); `fido_dev_t *` `fido_dev_new`(`void`); `fido_dev_t *` `fido_dev_new_with_info`(`const fido_dev_info_t *`); `void` `fido_dev_free`(`fido_dev_t **dev_p`); `void` `fido_dev_force_fido2`(`fido_dev_t *dev`); `void` `fido_dev_force_u2f`(`fido_dev_t *dev`); `bool` `fido_dev_is_fido2`(`const fido_dev_t *dev`); `bool` `fido_dev_is_winhello`(`const fido_dev_t *dev`); `bool` `fido_dev_supports_credman`(`const fido_dev_t *dev`); `bool` `fido_dev_supports_cred_prot`(`const fido_dev_t *dev`); `bool` `fido_dev_supports_permissions`(`const fido_dev_t *dev`); `bool` `fido_dev_supports_pin`(`const fido_dev_t *dev`); `bool` `fido_dev_supports_uv`(`const fido_dev_t *dev`); `bool` `fido_dev_has_pin`(`const fido_dev_t *dev`); `bool` `fido_dev_has_uv`(`const fido_dev_t *dev`); `uint8_t` `fido_dev_protocol`(`const fido_dev_t *dev`); `uint8_t` `fido_dev_build`(`const fido_dev_t *dev`); `uint8_t` `fido_dev_flags`(`const fido_dev_t *dev`); `uint8_t` `fido_dev_major`(`const fido_dev_t *dev`); `uint8_t` `fido_dev_minor`(`const fido_dev_t *dev`); # [DESCRIPTION](#DESCRIPTION) The [`fido_dev_open`](#fido_dev_open)() function opens the device pointed to by `path`, where `dev` is a freshly allocated or otherwise closed `fido_dev_t`. If `dev` claims to be FIDO2, *libfido2* will attempt to speak FIDO2 to `dev`. If that fails, *libfido2* will fallback to U2F unless the `FIDO_DISABLE_U2F_FALLBACK` flag was set in [fido\_init(3)](/man/os/libfido2/fido_init.3). The [`fido_dev_open_with_info`](#fido_dev_open_with_info)() function opens `dev` as previously allocated using `fido_dev_new_with_info`(). The [`fido_dev_close`](#fido_dev_close)() function closes the device represented by `dev`. If `dev` is already closed, `fido_dev_close`() is a NOP. The [`fido_dev_cancel`](#fido_dev_cancel)() function cancels any pending requests on `dev`. The [`fido_dev_new`](#fido_dev_new)() function returns a pointer to a newly allocated, empty `fido_dev_t`. If memory cannot be allocated, NULL is returned. The [`fido_dev_new_with_info`](#fido_dev_new_with_info)() function returns a pointer to a newly allocated `fido_dev_t` with `fido_dev_info_t` parameters, for use with [fido\_dev\_info\_manifest(3)](/man/os/libfido2/fido_dev_info_manifest.3) and `fido_dev_open_with_info`(). If memory cannot be allocated, NULL is returned. The [`fido_dev_free`](#fido_dev_free)() function releases the memory backing `*dev_p`, where `*dev_p` must have been previously allocated by `fido_dev_new`(). On return, `*dev_p` is set to NULL. Either `dev_p` or `*dev_p` may be NULL, in which case `fido_dev_free`() is a NOP. The [`fido_dev_force_fido2`](#fido_dev_force_fido2)() function can be used to force CTAP2 communication with `dev`, where `dev` is an open device. The [`fido_dev_force_u2f`](#fido_dev_force_u2f)() function can be used to force CTAP1 (U2F) communication with `dev`, where `dev` is an open device. The [`fido_dev_is_fido2`](#fido_dev_is_fido2)() function returns `true` if `dev` is a FIDO2 device. The [`fido_dev_is_winhello`](#fido_dev_is_winhello)() function returns `true` if `dev` is a Windows Hello device. The [`fido_dev_supports_credman`](#fido_dev_supports_credman)() function returns `true` if `dev` supports CTAP 2.1 Credential Management. The [`fido_dev_supports_cred_prot`](#fido_dev_supports_cred_prot)() function returns `true` if `dev` supports CTAP 2.1 Credential Protection. The [`fido_dev_supports_permissions`](#fido_dev_supports_permissions)() function returns `true` if `dev` supports CTAP 2.1 UV token permissions. The [`fido_dev_supports_pin`](#fido_dev_supports_pin)() function returns `true` if `dev` supports CTAP 2.0 Client PINs. The [`fido_dev_supports_uv`](#fido_dev_supports_uv)() function returns `true` if `dev` supports a built-in user verification method. The [`fido_dev_has_pin`](#fido_dev_has_pin)() function returns `true` if `dev` has a CTAP 2.0 Client PIN set. The [`fido_dev_has_uv`](#fido_dev_has_uv)() function returns `true` if `dev` supports built-in user verification and its user verification feature is configured. The [`fido_dev_protocol`](#fido_dev_protocol)() function returns the CTAPHID protocol version identifier of `dev`. The [`fido_dev_build`](#fido_dev_build)() function returns the CTAPHID build version number of `dev`. The [`fido_dev_flags`](#fido_dev_flags)() function returns the CTAPHID capabilities flags of `dev`. The [`fido_dev_major`](#fido_dev_major)() function returns the CTAPHID major version number of `dev`. The [`fido_dev_minor`](#fido_dev_minor)() function returns the CTAPHID minor version number of `dev`. For the format and meaning of the CTAPHID parameters returned by functions above, please refer to the FIDO Client to Authenticator Protocol (CTAP) specification. # [RETURN VALUES](#RETURN_VALUES) On success, `fido_dev_open`(), `fido_dev_open_with_info`(), and `fido_dev_close`() return `FIDO_OK`. On error, a different error code defined in `` is returned. # [SEE ALSO](#SEE_ALSO) [fido\_dev\_info\_manifest(3)](/man/os/libfido2/fido_dev_info_manifest.3), [fido\_dev\_set\_io\_functions(3)](/man/os/libfido2/fido_dev_set_io_functions.3), [fido\_init(3)](/man/os/libfido2/fido_init.3) May 25, 2018 Linux 4.19.0-gvisor --- Document: fido_dev_has_uv(3) from libfido2 1.17.0-r5 (Chainguard OS) Source: https://github.com/Yubico/libfido2