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DNS and Service Functions

struct hostent * gethostbyname (const char *hostname);

Given the hostname in hostname, gethostbyname() uses DNS to return a struct hostent structure. Note that this operation may block and should be cancelled using AbortAllDNSOperations().

Note that you should copy out the contents of this structure since it is internal to the library.

struct hostent * gethostbyaddr (const void *addr, size_t len, int family);

Given the IP address in addr, gethostbyaddr() uses DNS to return a hostent structure. Note that addr is a struct sockaddr_in *.

Note that you should copy out the contents of the returned structure since it is internal to the library.

int gethostname (char *name, size_t namelen);

Gets the local hostname and puts it in the buffer name, truncated to namelen. namelen should be the size of the buffer.

Returns 0 on success, -1 on error. If you get an error, call GetMITLibError() to find out the error code.

struct hostent * gethostaddr ();

gethostaddr() uses DNS to return a struct hostent structure for the local host. In a configuration such as NAT where DNS servers fail to answer for the local IP address, only the h_addr array of the returned structure is filled out and the hostname is left as an empty string. Note that this operation may block and should be cancelled using AbortAllDNSOperations().

Note that you should copy out the contents of the returned structure since it is internal to the library.

struct servent * getservent (void);

getservent() reads the next entry of the services database in Internet Config. The services database in IC is the equivalent of /etc/services on Unix machines.

A connection to Internet Config is opened, if necessary.

void endservent (void);

Closes the connection to Internet Config.

struct servent * getservbyname (const char *servname, const char *protname);

getservbyname() searches the services database in Internet Config from the beginning and finds the first entry for which the service name specified by servname matches the s_name member and the protocol name specified by protname matches the s_proto member. If protoname is NULL, any value of the s_proto member will be matched.

A connection to Internet Config is opened, if necessary.

struct servent * getservbyport (int port, const char *protname);

getservbyport() function searches the InternetConfig services database from the beginning and finds the first entry for which the port specified by port matches the s_port member and the protocol name specified by protname matches the s_proto member. If protname is NULL, any value of the s_proto member will be matched. The port argument must be in network byte order.

A connection to Internet Config is opened, if necessary.

Questions or comments? Send mail to macdev@mit.edu
Last updated on $Date: 2003/11/19 20:49:22 $
Last modified by $Author: smcguire $