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ares_gethostbyname(3) [centos man page]

ARES_GETHOSTBYNAME(3)					     Library Functions Manual					     ARES_GETHOSTBYNAME(3)

NAME
ares_gethostbyname - Initiate a host query by name SYNOPSIS
#include <ares.h> typedef void (*ares_host_callback)(void *arg, int status, int timeouts, struct hostent *hostent) void ares_gethostbyname(ares_channel channel, const char *name, int family, ares_host_callback callback, void *arg) DESCRIPTION
The ares_gethostbyname function initiates a host query by name on the name service channel identified by channel. The parameter name gives the hostname as a NUL-terminated C string, and family gives the desired type of address for the resulting host entry. When the query is complete or has failed, the ares library will invoke callback. Completion or failure of the query may happen immediately, or may happen during a later call to ares_process(3), ares_destroy(3) or ares_cancel(3). The callback argument arg is copied from the ares_gethostbyname argument arg. The callback argument status indicates whether the query succeeded and, if not, how it failed. It may have any of the following values: ARES_SUCCESS The host lookup completed successfully. ARES_ENOTIMP The ares library does not know how to find addresses of type family. ARES_EBADNAME The hostname name is composed entirely of numbers and periods, but is not a valid representation of an Internet address. ARES_ENOTFOUND The address addr was not found. ARES_ENOMEM Memory was exhausted. ARES_ECANCELLED The query was cancelled. ARES_EDESTRUCTION The name service channel channel is being destroyed; the query will not be completed. The callback argument timeouts reports how many times a query timed out during the execution of the given request. On successful completion of the query, the callback argument hostent points to a struct hostent containing the name of the host returned by the query. The callback need not and should not attempt to free the memory pointed to by hostent; the ares library will free it when the callback returns. If the query did not complete successfully, hostent will be NULL. SEE ALSO
ares_process(3), ares_gethostbyaddr(3) AUTHOR
Greg Hudson, MIT Information Systems Copyright 1998 by the Massachusetts Institute of Technology. 25 July 1998 ARES_GETHOSTBYNAME(3)

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ARES_SEND(3)						     Library Functions Manual						      ARES_SEND(3)

NAME
ares_send - Initiate a DNS query SYNOPSIS
#include <ares.h> typedef void (*ares_callback)(void *arg, int status, int timeouts, unsigned char *abuf, int alen) void ares_send(ares_channel channel, const unsigned char *qbuf, int qlen, ares_callback callback, void *arg) DESCRIPTION
The ares_send function initiates a DNS query on the name service channel identified by channel. The parameters qbuf and qlen give the DNS query, which should already have been formatted according to the DNS protocol. When the query is complete or has failed, the ares library will invoke callback. Completion or failure of the query may happen immediately, or may happen during a later call to ares_process(3) or ares_destroy(3). The callback argument arg is copied from the ares_send argument arg. The callback argument status indicates whether the query succeeded and, if not, how it failed. It may have any of the following values: ARES_SUCCESS The query completed. ARES_EBADQUERY The query buffer was poorly formed (was not long enough for a DNS header or was too long for TCP transmission). ARES_ETIMEOUT No name servers responded within the timeout period. ARES_ECONNREFUSED No name servers could be contacted. ARES_ENOMEM Memory was exhausted. ARES_ECANCELLED The query was cancelled. ARES_EDESTRUCTION The name service channel channel is being destroyed; the query will not be completed. The callback argument timeouts reports how many times a query timed out during the execution of the given request. If the query completed, the callback argument abuf points to a result buffer of length alen. If the query did not complete, abuf will be NULL and alen will be 0. Unless the flag ARES_FLAG_NOCHECKRESP was set at channel initialization time, ares_send will normally ignore responses whose questions do not match the questions in qbuf, as well as responses with reply codes of SERVFAIL, NOTIMP, and REFUSED. Unlike other query functions in the ares library, however, ares_send does not inspect the header of the reply packet to determine the error status, so a callback status of ARES_SUCCESS does not reflect as much about the response as for other query functions. SEE ALSO
ares_process(3) AUTHOR
Greg Hudson, MIT Information Systems Copyright 1998 by the Massachusetts Institute of Technology. 25 July 1998 ARES_SEND(3)
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