bson_oid_t - Man Page

#include <bson/bson.h>

typedef struct {
   uint8_t bytes[12];
} bson_oid_t;

The bson_oid_t <> structure contains the 12-byte ObjectId notation defined by the BSON ObjectID specification <https://www.mongodb.com/docs/manual/reference/object-id/>.

ObjectId is a 12-byte BSON type, constructed using:

• a 4-byte value representing the seconds since the Unix epoch (in Big Endian).
• a 5-byte random value.
• a 3-byte counter (Big Endian), starting with a random value.

You can convert an Object ID to a string using bson_oid_to_string() <> and back with bson_oid_init_from_string() <>.

A bson_oid_t <> can be used in hashtables using the function bson_oid_hash() <> and bson_oid_equal() <>.

A bson_oid_t <> can be compared to another using bson_oid_compare() <> for qsort() style comparing and bson_oid_equal() <> for direct equality.

You can validate that a string containing a hex-encoded ObjectID is valid using the function bson_oid_is_valid() <>.

#include <bson/bson.h>
#include <stdio.h>

int
main (int argc, char *argv[])
{
   bson_oid_t oid;
   char str[25];

   bson_oid_init (&oid, NULL);
   bson_oid_to_string (&oid, str);
   printf ("%s\n", str);

   if (bson_oid_is_valid (str, sizeof str)) {
      bson_oid_init_from_string (&oid, str);
   }

   printf ("The UNIX time was: %u\n", (unsigned) bson_oid_get_time_t (&oid));

   return 0;
}

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