#define BSON_APPEND_UTF8(b, key, val) \
   bson_append_utf8 (b, key, (int) strlen (key), val, (int) strlen (val))

bson_append_utf8 (bson_t *bson,
                  const char *key,
                  int key_length,
                  const char *value,
                  int length);


  • 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: A UTF-8 encoded string.
  • length: The number of bytes in value excluding the trailing \0, or -1 to determine the length with strlen().


The bson_append_utf8() function shall append a UTF-8 encoded string to bson.

value MUST be valid UTF-8.

Some UTF-8 implementations allow for \0 to be contained within the string (excluding the termination \0. This is allowed, but remember that it could cause issues with communicating with external systems that do not support it.

It is suggested to use modified UTF-8 which uses a 2 byte representation for embedded \0 within the string. This will allow these UTF-8 encoded strings to used with many libc functions.


Returns true if the operation was applied successfully. The function will fail if appending the value grows bson larger than INT32_MAX.