---
name: "bson_append_symbol"
section: "3"
platform: "linux"
package: "libbson-doc"
version: "1.30.4-1+deb13u3"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/bson_append_symbol"
---

# bson\_append\_symbol(3)

## SYNOPSIS

```
#define BSON_APPEND_SYMBOL(b, key, val) \
   bson_append_symbol (b, key, (int) strlen (key), val, (int) strlen (val))
bool
bson_append_symbol (bson_t *bson,
                    const char *key,
                    int key_length,
                    const char *value,
                    int length);
```

## PARAMETERS

- •

  **bson**: A *bson\_t*.

- •

  **key**: An ASCII C string containing the name of the field.

- •

  **key\_length**: The length of **key** in bytes, or -1 to determine the length with **strlen()**.

- •

  **value**: The symbol.

- •

  **length**: A length of **symbol** in bytes, or -1 to determine the length with **strlen()**.

## DESCRIPTION

Appends a new field to **bson** of type BSON\_TYPE\_SYMBOL. This BSON type is deprecated and should not be used in new code.

Due to legacy behavior, passing **NULL** for **value** appends a null value, *not* a symbol value. To append a null value directly, prefer using *bson\_append\_null()*.

## RETURNS

Returns **true** if the operation was applied successfully. The function will fail if appending the value grows **bson** larger than INT32\_MAX.

## AUTHOR

MongoDB, Inc

## COPYRIGHT

2009-present, MongoDB, Inc.