---
name: "radcli_avp_concat_str_by_num"
section: "3"
platform: "linux"
package: "radcli"
version: "2.0.1-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/radcli_avp_concat_str_by_num"
---

# radcli\_avp\_concat\_str\_by\_num(3)

Look up an attribute by legacy numeric ID and concatenate every occurrence into a bounded buffer.

## NAME

radcli\_avp\_concat\_str\_by\_num - Look up an attribute by legacy numeric ID and concatenate every occurrence into a bounded buffer.

## SYNOPSIS

```
#include <radcli/>

int radcli_avp_concat_str_by_num(
    char                   *buf,
    size_t                  buflen,
    const radcli_avp_list  *list,
    const radcli_ctx       *ctx,
    uint32_t                attrid,
    uint32_t                vendor,
    const char             *sep
);
```

## DESCRIPTION

The \_by\_num() wrapper for radcli\_avp\_concat\_str(): equivalent to radcli\_avp\_concat\_str(buf, buflen, l, radcli\_dict\_lookup\_num(ctx, attrid,

vendor), sep), except that an unresolvable attribute ID is not itself a failure here  it is treated the same as "no occurrence present" (buf set to an empty string, 0 returned), matching this function's legacy-ID convenience role: a caller passing a well-known PW\_\* constant should not have to separately handle "not in this dictionary" as an error case, the same way rc\_aaa()'s msg never failed just because a reply had no Reply-Message.

## PARAMETERS

- **buf**

  destination buffer, or NULL to only compute the needed size; see radcli\_avp\_concat\_str().

- **buflen**

  size of buf, in bytes; may be 0.

- **list**

  the list to search.

- **ctx**

  a context with a dictionary loaded.

- **attrid**

  the attribute ID (a PW\_\* constant, or a vendor type ID when vendor is non-zero).

- **vendor**

  the vendor PEN, or 0 for a standard attribute.

- **sep**

  separator inserted between occurrences; NULL or "" for none.

## RETURN VALUE

the number of bytes the joined result occupies (excluding the NUL terminator), whether or not it fit in buf; 0 if attrid/vendor resolves to no attribute.

## SEE ALSO

[*radcli\_avp\_add\_bytes*(3)](/radcli_avp_add_bytes/3.md), [*radcli\_avp\_add\_bytes\_by\_num*(3)](/radcli_avp_add_bytes_by_num/3.md), [*radcli\_avp\_add\_gigawords64*(3)](/radcli_avp_add_gigawords64/3.md), [*radcli\_avp\_add\_gigawords64\_by\_num*(3)](/radcli_avp_add_gigawords64_by_num/3.md), [*radcli\_avp\_add\_ip4*(3)](/radcli_avp_add_ip4/3.md), [*radcli\_avp\_add\_ip4\_by\_num*(3)](/radcli_avp_add_ip4_by_num/3.md), [*radcli\_avp\_add\_ip4prefix*(3)](/radcli_avp_add_ip4prefix/3.md), [*radcli\_avp\_add\_ip4prefix\_by\_num*(3)](/radcli_avp_add_ip4prefix_by_num/3.md), [*radcli\_avp\_add\_ip6*(3)](/radcli_avp_add_ip6/3.md), [*radcli\_avp\_add\_ip6\_by\_num*(3)](/radcli_avp_add_ip6_by_num/3.md), [*radcli\_avp\_add\_str*(3)](/radcli_avp_add_str/3.md), [*radcli\_avp\_add\_str\_by\_num*(3)](/radcli_avp_add_str_by_num/3.md), [*radcli\_avp\_add\_uint32*(3)](/radcli_avp_add_uint32/3.md), [*radcli\_avp\_add\_uint32\_by\_num*(3)](/radcli_avp_add_uint32_by_num/3.md), [*radcli\_avp\_add\_uint64*(3)](/radcli_avp_add_uint64/3.md), [*radcli\_avp\_add\_uint64\_by\_num*(3)](/radcli_avp_add_uint64_by_num/3.md), [*radcli\_avp\_add\_username*(3)](/radcli_avp_add_username/3.md), [*radcli\_avp\_concat\_str*(3)](/radcli_avp_concat_str/3.md), [*radcli\_avp\_def*(3)](/radcli_avp_def/3.md), [*radcli\_avp\_get*(3)](/radcli_avp_get/3.md), [*radcli\_avp\_get\_by\_num*(3)](/radcli_avp_get_by_num/3.md), [*radcli\_avp\_get\_bytes*(3)](/radcli_avp_get_bytes/3.md), [*radcli\_avp\_get\_bytes\_by\_num*(3)](/radcli_avp_get_bytes_by_num/3.md), [*radcli\_avp\_get\_cstr*(3)](/radcli_avp_get_cstr/3.md), [*radcli\_avp\_get\_cstr\_by\_num*(3)](/radcli_avp_get_cstr_by_num/3.md), [*radcli\_avp\_get\_gigawords64*(3)](/radcli_avp_get_gigawords64/3.md), [*radcli\_avp\_get\_gigawords64\_by\_num*(3)](/radcli_avp_get_gigawords64_by_num/3.md), [*radcli\_avp\_get\_ip4prefix*(3)](/radcli_avp_get_ip4prefix/3.md), [*radcli\_avp\_get\_ip4prefix\_by\_num*(3)](/radcli_avp_get_ip4prefix_by_num/3.md), [*radcli\_avp\_get\_ip6*(3)](/radcli_avp_get_ip6/3.md), [*radcli\_avp\_get\_ip6\_by\_num*(3)](/radcli_avp_get_ip6_by_num/3.md), [*radcli\_avp\_get\_uint32*(3)](/radcli_avp_get_uint32/3.md), [*radcli\_avp\_get\_uint32\_by\_num*(3)](/radcli_avp_get_uint32_by_num/3.md), [*radcli\_avp\_get\_uint64*(3)](/radcli_avp_get_uint64/3.md), [*radcli\_avp\_get\_uint64\_by\_num*(3)](/radcli_avp_get_uint64_by_num/3.md), [*radcli\_avp\_iter\_next*(3)](/radcli_avp_iter_next/3.md), [*radcli\_avp\_list\_error*(3)](/radcli_avp_list_error/3.md), [*radcli\_avp\_list\_free*(3)](/radcli_avp_list_free/3.md), [*radcli\_avp\_list\_iter*(3)](/radcli_avp_list_iter/3.md), [*radcli\_avp\_list\_new*(3)](/radcli_avp_list_new/3.md)