bson_iter_init (3) - Linux Manuals

bson_iter_init: The bson_iter_init() function shall initialize iter to iterate upon the BSON document bson. Upon initialization, iter is placed before the first element. Callers must call bson_iter_next(), bson_iter_find(), or bson_iter_find_case() to advance to an element.

Command to display bson_iter_init manual in Linux: $ man 3 bson_iter_init

NAME

bson_iter_init() - The bson_iter_init() function shall initialize iter to iterate upon the BSON document bson. Upon initialization, iter is placed before the first element. Callers must call bson_iter_next(), bson_iter_find(), or bson_iter_find_case() to advance to an element.

SYNOPSIS

bool
bson_iter_init (bson_iter_t  *iter,
                const bson_t *bson);

PARAMETERS

iter: A bson_iter_t \&.

bson: A bson_t \&.

DESCRIPTION

The bson_iter_init(3) function shall initialize iter to iterate upon the BSON document bson \&. Upon initialization, iter is placed before the first element. Callers must call bson_iter_next(3) , bson_iter_find(3) , or bson_iter_find_case(3) to advance to an element.

RETURNS

Returns true if the iter was successfuly initialized.

EXAMPLE

static void
print_doc_id (const bson_t *doc)
{
   bson_iter_t iter;
   bson_oid_t oid;
   char oidstr[25];

   if (bson_iter_init (&iter, doc) &&
       bson_iter_find (&iter, "_id") &&
       BSON_ITER_HOLDS_OID (&iter)) {
      bson_iter_oid (&iter, &oid);
      bson_oid_to_string (&oid, oidstr);
      printf ("%s\n", oidstr);
   } else {
      printf ("Document is missing _id.\n");
   }
}

/* alternatively */

static void
print_doc_id (const bson_t *doc)
{
   bson_iter_t iter;
   bson_oid_t oid;
   char oidstr[25];

   if (bson_iter_init_find (&iter, doc, "_id") &&
       BSON_ITER_HOLDS_OID (&iter)) {
      bson_iter_oid (&iter, &oid);
      bson_oid_to_string (&oid, oidstr);
      printf ("%s\n", oidstr);
   } else {
      printf ("Document is missing _id.\n");
   }
}

COLOPHON

This page is part of libbson. Please report any bugs at https://jira.mongodb.org/browse/CDRIVER.

Pages related to bson_iter_init

bson_iter_init_find (3) - This function is identical to (bson_iter_init() && bson_iter_find()).
bson_iter_init_find_case (3) - This function is identical to bson_iter_init() && bson_iter_find_case().
bson_iter_int32 (3) - Fetches the value from a BSON_TYPE_INT32 element. You should verify that the field is a BSON_TYPE_INT32 field before calling this function.
bson_iter_int64 (3) - Fetches the value from a BSON_TYPE_INT64 field. You should verify that this is a BSON_TYPE_INT64 field before calling this function.
bson_iter_array (3) - The bson_iter_array() function shall retrieve the raw buffer of a sub-array from iter. iter MUST be on an element that is of type BSON_TYPE_ARRAY. This can be verified with bson_iter_type() or the BSON_ITER_HOLDS_ARRAY() macro.
bson_iter_as_bool (3) - Fetches the current field as if it were a boolean.
bson_iter_as_int64 (3) - The bson_iter_as_int64() function shall return the contents of the current element as if it were a BSON_TYPE_INT64 element. The currently supported casts include:
bson_iter_binary (3) - This function shall return the binary data of a BSON_TYPE_BINARY element. It is a programming error to call this function on a field that is not of type BSON_TYPE_BINARY. You can check this with the BSON_ITER_HOLDS_BINARY() macro or bson_iter_type().
bson_iter_bool (3) - The bson_iter_bool()function shall return the boolean value of a BSON_TYPE_BOOL element. It is a programming error to call this function on an element other than BSON_TYPE_BOOL. You can check this with bson_iter_type() or BSON_ITER_HOLDS_BOOL().
bson_iter_code (3) - This function returns the contents of a BSON_TYPE_CODE field. The length of the string is stored in length if non-NULL.
bson_iter_codewscope (3) - The bson_iter_codewscope() function acts similar to bson_iter_code() except for BSON_TYPE_CODEWSCOPE elements. It also will provide a pointer to the buffer for scope, which can be loaded into a bson_t using bson_init_static().
bson_iter_date_time (3) - The bson_iter_date_time() function shall return the number of miliseconds since the UNIX epoch, as contained in the BSON_TYPE_DATE_TIME element.
bson_iter_dbpointer (3) - Fetches the contents of a BSON_TYPE_DBPOINTER element.
bson_iter_document (3) - The bson_iter_document() function shall retrieve the raw buffer of a sub-document from iter. iter MUST be on an element that is of type BSON_TYPE_DOCUMENT. This can be verified with bson_iter_type() or the BSON_ITER_HOLDS_DOCUMENT() macro.