tfGetHostByName

Table of Contents >> Application Reference >> DNS Resolver

#include <trsocket.h>

int tfGetHostByName	(
	const char TM_FAR * hostnameStr,
	struct tsHostent TM_FAR * TM_FAR * hostEntryPtrPtr
	);

Function Description

Retrieve all host addresses for the specified hostname. This function is similar to Treck functions getaddrinfo() and tfDnsGetHostByName() except this function will first search the Hosts Table for a matching hostname. If there is no entry in the Hosts Table for hostnameStr, this function will generate a DNS query in an attempt to resolve the name externally. The information returned by this function is snapshot of potentially transient data. The volatile data is copied into a dynamically allocated block of memory, to which a pointer is returned. The caller must eventually free the block by calling tfFreeHostEntry() with the pointer returned by this function.

Parameters

• hostnameStr

  Name of the host to resolve to an IP address.

• hostEntryPtrPtr

  Pointer to a variable to receive a pointer to the data.

Note:

The caller must eventually call tfFreeHostEntry() with the pointer returned by this function when the host information is no longer needed.

Returns

• TM_ENOERROR

  Success.

• TM_EPERM

  Call tfDnsInit() first.

• TM_EINVAL

  A NULL pointer was provided.

• TM_ENOMEM

  Memory allocation failed.

• TM_EAFNOSUPPORT

  addressPtr or addressFamily is not AF_INET or AF_INET6.

• TM_EWOULDBLOCK

  DNS lookup in progress. The user should continue to call this function with the same parameters until it returns a value other than TM_EWOULDBLOCK.

• TM_ENOBUFS

  Insufficient packet buffers.

• TM_EFILE

  Treck was unable to successfully allocate a socket for the DNS request. This could indicate Treck did not have the resources to allocate another socket. It could also be due to Treck hitting the limit of sockets set by TM_DNS_MAX_SOCKETS_ALLOWED or the tfDnsSetOption() option: TM_DNS_OPTION_MAX_SOCKETS_ALLOWED.

• TM_ETIMEDOUT

  DNS server failed to respond in a timely fashion.

• TM_EHOSTUNREACH

  No route to DNS server.

• TM_DNS_EANSWER

  No answer from the name server.

• TM_DNS_ECACHE_FULL

  Response lost, internal DNS cache is full.

• TM_EINPROGRESS

  Cannot replace a cache entry that is currently being used.

Table of Contents >> Application Reference >> DNS Resolver