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_name | Pointer to a string that contains the host name. |
p_res_host_name | Pointer to a string that will receive the host name resulting from a reverse lookup OR the canonical name resulting from a forward lookup with the DNSc_FLAG_CANON set. |
res_hostname_len | String length of p_res_host_name. This argument should evaluate to 0 if a simple forward DNS request is desired (with DNSc_FLAG_CANON cleared). |
p_addrs | Pointer to arrays that will receive the IP address(es) from this function. |
p_addr_nbr | Pointer to a variable that: (1) Indicates how many addresses can fit into the addresses array pointed by the 'p_addrs' argument. If the caller desires a reverse lookup, the variable should evaluate to 1. and (2) Will receive the number of address(es) copied into the addresses array. |
flags | DNS client flag: DNSc_FLAG_NONE - By default this function is blocking. |
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_err | Pointer 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
(1) The DNSc_FLAG_REVERSE_LOOKUP flag must be used in conjunction with the DNSc_FLAG_FORCE_RESOLUTION flag.
(2) If this function successfully resolves a reverse lookup, the host's information is added to the cache just as it would be for a forward lookup.
Example Usage
See Sample Application.