---
name: "fido_dev_info_vendor"
section: "3"
platform: "linux"
package: "libfido2"
version: "1.17.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/fido_dev_info_manifest"
---

# fido\_dev\_info\_vendor(3)

FIDO2 device discovery functions

Part of [fido\_dev\_info\_manifest(3)](/fido_dev_info_manifest/3.md).

## NAME

**fido\_dev\_info\_manifest**, **fido\_dev\_info\_new**, **fido\_dev\_info\_free**, **fido\_dev\_info\_ptr**, **fido\_dev\_info\_path**, **fido\_dev\_info\_product**, **fido\_dev\_info\_vendor**, **fido\_dev\_info\_manufacturer\_string**, **fido\_dev\_info\_product\_string**, **fido\_dev\_info\_set** – FIDO2 device discovery functions

## SYNOPSIS

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

*int*\

**fido\_dev\_info\_manifest**(*fido\_dev\_info\_t \*devlist*, *size\_t ilen*, *size\_t \*olen*);

*fido\_dev\_info\_t* *\**\

**fido\_dev\_info\_new**(*size\_t n*);

*void*\

**fido\_dev\_info\_free**(*fido\_dev\_info\_t \*\*devlist\_p*, *size\_t n*);

*const* *fido\_dev\_info\_t* *\**\

**fido\_dev\_info\_ptr**(*const fido\_dev\_info\_t \*devlist*, *size\_t i*);

*const* *char* *\**\

**fido\_dev\_info\_path**(*const fido\_dev\_info\_t \*di*);

*int16\_t*\

**fido\_dev\_info\_product**(*const fido\_dev\_info\_t \*di*);

*int16\_t*\

**fido\_dev\_info\_vendor**(*const fido\_dev\_info\_t \*di*);

*const* *char* *\**\

**fido\_dev\_info\_manufacturer\_string**(*const fido\_dev\_info\_t \*di*);

*const* *char* *\**\

**fido\_dev\_info\_product\_string**(*const fido\_dev\_info\_t \*di*);

*int*\

**fido\_dev\_info\_set**(*fido\_dev\_info\_t \*devlist*, *size\_t i*, *const char \*path*, *const char \*manufacturer*, *const char \*product*, *const fido\_dev\_io\_t \*io*, *const fido\_dev\_transport\_t \*transport*);

## DESCRIPTION

The **fido\_dev\_info\_manifest**() function fills *devlist* with up to *ilen* FIDO2 devices found by the underlying operating system. Currently only USB HID devices are supported. The number of discovered devices is returned in *olen*, where *olen* is an addressable pointer.

The **fido\_dev\_info\_new**() function returns a pointer to a newly allocated, empty device list with *n* available slots. If memory is not available, NULL is returned.

The **fido\_dev\_info\_free**() function releases the memory backing *\*devlist\_p*, where *\*devlist\_p* must have been previously allocated by **fido\_dev\_info\_new**(). The number *n* of allocated slots must also be provided. On return, *\*devlist\_p* is set to NULL. Either *devlist\_p* or *\*devlist\_p* may be NULL, in which case **fido\_dev\_info\_free**() is a NOP.

The **fido\_dev\_info\_ptr**() function returns a pointer to slot number *i* of *devlist*. It is the caller's responsibility to ensure that *i* is bounded. Please note that the first slot has index 0.

The **fido\_dev\_info\_path**() function returns the filesystem path or subsystem-specific identification string of *di*.

The **fido\_dev\_info\_product**() function returns the product ID of *di*.

The **fido\_dev\_info\_vendor**() function returns the vendor ID of *di*.

The **fido\_dev\_info\_manufacturer\_string**() function returns the manufacturer string of *di*. If *di* does not have an associated manufacturer string, **fido\_dev\_info\_manufacturer\_string**() returns an empty string.

The **fido\_dev\_info\_product\_string**() function returns the product string of *di*. If *di* does not have an associated product string, **fido\_dev\_info\_product\_string**() returns an empty string.

An example of how to use the functions described in this document can be found in the *examples/manifest.c* file shipped with *libfido2*.

The **fido\_dev\_info\_set**() function initializes an entry in a device list allocated by **fido\_dev\_info\_new**() with the specified path, manufacturer, and product strings, and with the specified I/O handlers and, optionally, transport functions, as described in [fido\_dev\_set\_io\_functions(3)](/fido_dev_set_io_functions/3.md). The *io* argument must be specified; the *transport* argument may be NULL. The path, I/O handlers, and transport functions will be used automatically by [fido\_dev\_new\_with\_info(3)](/fido_dev_new_with_info/3.md) and [fido\_dev\_open\_with\_info(3)](/fido_dev_open_with_info/3.md). An application can use this, for example, to substitute mock FIDO2 devices in testing for the real ones that **fido\_dev\_info\_manifest**() would discover.

## RETURN VALUES

The **fido\_dev\_info\_manifest**() function always returns FIDO\_OK. If a discovery error occurs, the *olen* pointer is set to 0.

On success, the **fido\_dev\_info\_set**() function returns FIDO\_OK. On error, a different error code defined in ⟨fido/err.h⟩ is returned.

The pointers returned by **fido\_dev\_info\_ptr**(), **fido\_dev\_info\_path**(), **fido\_dev\_info\_manufacturer\_string**(), and **fido\_dev\_info\_product\_string**() are guaranteed to exist until **fido\_dev\_info\_free**() is called on the corresponding device list.