char *
bson_as_json (const bson_t *bson, size_t *length);


  • bson: A bson_t.

  • length: An optional location for the length of the resulting string.


The bson_as_json() function shall encode bson as a UTF-8 string using libbson’s legacy JSON format. This function is superseded by bson_as_canonical_extended_json() and bson_as_relaxed_extended_json(), which use the same MongoDB Extended JSON format as all other MongoDB drivers.

The caller is responsible for freeing the resulting UTF-8 encoded string by calling bson_free() with the result.

If non-NULL, length will be set to the length of the result in bytes.


If successful, a newly allocated UTF-8 encoded string and length is set.

Upon failure, NULL is returned.


#include <bson/bson.h>

int main ()
   bson_t bson;
   char *str;

   bson_init (&bson);
   BSON_APPEND_UTF8 (&bson, "0", "foo");
   BSON_APPEND_UTF8 (&bson, "1", "bar");

   str = bson_as_json (&bson, NULL);
   /* Prints
    * { "0" : "foo", "1" : "bar" }
   printf ("%s\n", str);
   bson_free (str);

   bson_destroy (&bson);