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Converts the string representation of a host name to its corresponding IP address using DNS service.

Files

dns-c.h/dns-c.c

Prototype

Arguments

p_host_namePointer to

...

a string that contains the host name.

Returned Values

IP address of the host, if no errors;

NET_IP_ADDR_NONE, otherwise.

Required Configuration

None.

Notes / Warnings

This function is a simplified version of BSD socket API’s gethostbyname(). Given a domain name, this function will first query a locally maintained cache and, if no match is found, it will issue a DNS query to retrieve the host’s IP address.

p_addrsPointer to arrays that will receive the IP address from this function.
flags

DNS client flag:

DNSc_FLAG_NONE By default this function is blocking.
DNSc_FLAG_NO_BLOCK Don't block (only possible if DNSc's task is enabled).
DNSc_FLAG_FORCE_CACHE Take host from the cache, don't send new DNS request.
DNSc_FLAG_FORCE_RENEW Force DNS request, remove existing entry in the cache.
DNSc_FLAG_IPv4_ONLY Return only IPv4 address(es).
DNSc_FLAG_IPv6_ONLY Return only IPv6 address(es).

p_cfg

Must be set to DEF_NULL to use default configuration.

Pointer to a request configuration. Should be set to overwrite default DNS configuration (such as DNS server, request timeout, etc.).

p_errPointer to variable that will receive the return error code from this function.

Returned Values

Resolution status:

DNSc_STATUS_PENDING  Host resolution is pending, call again to see the status. (Processed by DNSc's task)
DNSc_STATUS_RESOLVED Host is resolved.
DNSc_STATUS_FAILED   Host resolution has failed.

Required Configuration

None.

Notes / Warnings

None.

Example Usage

See Sample Application.