Counters

Detailed Description

Manipulate the numeric content of a document

Counter operations treat the document being accessed as a numeric value (the document should contain a parseable integer as its content). This value may then be incremented or decremented.

Function Documentation

lcb_cmdcounter_on_behalf_of()

lcb_STATUS lcb_cmdcounter_on_behalf_of	(	lcb_CMDCOUNTER *	cmd,
		const char *	data,
		size_t	data_len )

Stability

Internal

Internal: This should never be used and is not supported.

lcb_cmdcounter_on_behalf_of_extra_privilege()

lcb_STATUS lcb_cmdcounter_on_behalf_of_extra_privilege	(	lcb_CMDCOUNTER *	cmd,
		const char *	privilege,
		size_t	privilege_len )

Stability

Internal

Internal: This should never be used and is not supported.

Typedef Documentation

lcb_RESPCOUNTER

typedef struct lcb_RESPCOUNTER_ lcb_RESPCOUNTER

Schedule single counter operation.

Stability

Committed

Parameters

instance	the instance
cookie	the pointer to associate with the request
cmd	the command to use

Returns

LCB_SUCCESS on success, other error on failure

Request

lcb_CMDCOUNTER* cmd;
lcb_cmdcounter_create(&cmd);
lcb_cmdcounter_key(cmd, "counter", strlen("counter"));
lcb_cmdcounter_delta(cmd, 1); // Increment by one
lcb_cmdcounter_value(cmd, 42); // Default value is 42 if it does not exist
lcb_cmdcounter_expiry(cmd, 300); // Expire in 5 minutes
lcb_counter(instance, NULL, cmd);
lcb_wait(instance, LCB_WAIT_NOCHECK);

Response

lcb_install_callback(instance, LCB_CALLBACKTYPE_COUNTER, counter_cb);
void counter_cb(lcb_INSTANCE *instance, int cbtype, const lcb_RESPBASE *rb)
{
    const lcb_RESPCOUNTER *resp = (const lcb_RESPCOUNTER *)rb;
    lcb_STATUS = lcb_respcounter_status(resp);
    if (rc == LCB_SUCCESS) {
        char* key;
        size_t key_len;
        uint64_t value;
        lcb_respcounter_value(resp, &value);
        lcb_respcounter_key(resp, &key, &key_len);
        printf("Incremented counter for %.*s. Current value %llu\n",
               key_len, key, value);
    }
}

Callback Errors

In addition to generic errors, the following errors may be returned in the callback (via lcb_respcounter_status):

• ::LCB_ERR_DOCUMENT_NOT_FOUND if the counter doesn't exist
• ::LCB_ERR_INVALID_DELTA if the existing document's content could not be parsed as a number by the server.