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NE_ADDR_RESOLVE

Section: neon API reference (3)
Updated: 30 September 2016
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NAME

ne_addr_resolve, ne_addr_result, ne_addr_first, ne_addr_next, ne_addr_error, ne_addr_destroy - functions to resolve hostnames to addresses

SYNOPSIS

#include <ne_socket.h>

ne_sock_addr *ne_addr_resolve(const char *hostname, int flags);
int ne_addr_result(const ne_sock_addr *addr);
const ne_inet_addr *ne_addr_first(ne_sock_addr *addr);
const ne_inet_addr *ne_addr_next(ne_sock_addr *addr);
char *ne_addr_error(const ne_sock_addr *addr, char *buffer, size_t bufsiz);
void ne_addr_destroy(ne_sock_addr *addr);

DESCRIPTION

The ne_addr_resolve function resolves the given hostname, returning an ne_sock_addr object representing the address (or addresses) associated with the hostname. The flags parameter is currently unused, and must be passed as 0.

The hostname passed to ne_addr_resolve can be a DNS hostname (e.g. "www.example.com") or an IPv4 dotted quad (e.g. "192.0.34.72"); or, on systems which support IPv6, an IPv6 hex address, which may be enclosed in brackets, e.g. "[::1]".

To determine whether the hostname was successfully resolved, the ne_addr_result function is used, which returns non-zero if an error occurred. If an error did occur, the ne_addr_error function can be used, which will copy the error string into a given buffer (of size bufsiz).

The functions ne_addr_first and ne_addr_next are used to retrieve the Internet addresses associated with an address object which has been successfully resolved. ne_addr_first returns the first address; ne_addr_next returns the next address after the most recent call to ne_addr_next or ne_addr_first, or NULL if there are no more addresses. The ne_inet_addr pointer returned by these functions can be passed to ne_sock_connect to connect a socket.

After the address object has been used, it should be destroyed using ne_addr_destroy.

RETURN VALUE

ne_addr_resolve returns a pointer to an address object, and never NULL. ne_addr_error returns the buffer parameter .

EXAMPLES

The code below prints out the set of addresses associated with the hostname www.google.com.

ne_sock_addr *addr;
char buf[256];

addr = ne_addr_resolve("www.google.com", 0);
if (ne_addr_result(addr)) {
    printf("Could not resolve www.google.com: %s\n",
           ne_addr_error(addr, buf, sizeof buf));
} else {
    const ne_inet_addr *ia;
    printf("www.google.com:");
    for (ia = ne_addr_first(addr); ia != NULL; ia = ne_addr_next(addr)) {
        printf(" %s", ne_iaddr_print(ia, buf, sizeof buf));
    }
    putchar('\n');
}
ne_addr_destroy(addr);

AUTHOR

Joe Orton <neon@lists.manyfish.co.uk>

: Author.

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