Updated: April 19, 2023 |
Send a preformatted Internet domain name query
#include <sys/types.h> #include <netinet/in.h> #include <arpa/nameser.h> #include <resolv.h> int res_send( const u_char * msg, int msglen, u_char * answer, int anslen );
The res_send() function is a low-level routine that's used by res_query() to send a preformatted Internet domain name query and return an answer. It calls res_init() if RES_INIT isn't set, sends the query to the local name server, and handles timeouts and retries.
The resolver routines are used for making, sending, and interpreting query and reply messages with Internet domain name servers.
Global configuration and state information used by the resolver routines is kept in the structure _res. For more information on the options, see res_init().
Based on:
RFC 974, RFC 1032, RFC 1033, RFC 1034, RFC 1035
The length of a reply message, in bytes; or -1 if an error occurs.
Safety: | |
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Cancellation point | Yes |
Interrupt handler | No |
Signal handler | No |
Thread | No |