ARES_CANCEL(3) Library Functions Manual ARES_CANCEL(3)NAME
ares_cancel - Cancel a resolve
void ares_cancel(ares_channel channel)
The ares_cancel function cancels all lookups/requests made on the the name service channel identified by channel. ares_cancel invokes the
callbacks for each pending query on the channel, passing a status of ARES_ECANCELLED. These calls give the callbacks a chance to clean up
any state which might have been stored in their arguments. If such a callback invocation adds a new request to the channel, that request
will not be cancelled by the current invocation of ares_cancel.
SEE ALSO ares_init(3)ares_destroy(3)NOTES
This function was added in c-ares 1.2.0
c-ares 1.6.0 and earlier pass a status of ARES_ETIMEOUT instead of ARES_ECANCELLED.
31 March 2004 ARES_CANCEL(3)
Check Out this Related Man Page
ARES_GETHOSTBYNAME(3) Library Functions Manual ARES_GETHOSTBYNAME(3)NAME
ares_gethostbyname - Initiate a host query by name
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)
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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