res_setservers()--Set Name Server Addresses

 #include <resolv.h>

 void res_setservers(state* res,
                     union res_sockaddr_union *addresses,
                     int num_addresses)

The res_setservers() function sets the list of name server addresses that will be used on resolver or network APIs that use the state structure.

Parameters

res

(Input) The pointer to the state structure.

addresses

(Input) A pointer to a list of name server addresses to use. The structure of each address entry is:

union res_sockaddr_union {
    struct sockaddr_in  sin;
    struct sockaddr_in6 sin6;
    int64_t         __align64;  /* 64bit alignment */
    char            __space[128];   /* max size */
};

num_addresses

(Input) The number of addresses in the list. The maximum number of addresses is MAXNS.

Authorities

No authorization is required.

Return Value

None.

Error Conditions

When the res_setservers() function fails, errno will be set to one of the following:

[EFAULT]

The system detected a pointer that was invalid while attempting to access an input pointer.

[EINVAL]

res appears to have been previously initialized but the reserved field is not set to zeros.

Usage Notes

1. res_setservers() replaces the entire list of existing name server addresses with the new list. If the new list has fewer than MAXNS entries, the remaining entries will be set to null.
2. If more than MAXNS entries are used, only MAXNS entries will be set and extra entries will be ignored.

Related Information

• res_ninit()--Initialize res Structure
  
  
• res_nclose()--Close Socket and Reset res Structure
  
  
• res_getservers()--Get Name Server Addresses

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