Gets network host entry by name.
Standard C Library (libc.a) (libbind) (libnis) (liblocal)
#include netdb.h> int gethostbyname_r(Name, Htent, Ht_data) const char *Name, struct hostent *Htent, struct hostent_data *Ht_data;
This function internally calls the gethostbyname subroutine and stores the value returned by the gethostbyname subroutine to the hostent structure.
| Name | Points to the host name (which is a constant). |
| Htent | Points to a hostent structure in which the return value of the gethostbyname subroutine is stored. |
| Ht_data | Points to a hostent_data structure. |
The function returns a 0 if successful and a -1 if unsuccessful.
The return value of the gethostbyname subroutine points to static data that is overwritten by subsequent calls. This data must be copied at every call to be saved for use by subsequent calls. The gethostbyname_r subroutine solves this problem.
If the Name parameter is an IP address, this subroutine searches for a machine with that IP address as a name. Because of this, use the gethostbyaddr_r subroutine instead of the gethostbyname_r subroutine if the Name parameter is an IP address.
The gethostbyname_r subroutine is unsuccessful if any of the following errors occurs:
| HOST_NOT_FOUND | The host specified by the Name parameter was not found. |
| TRY_AGAIN | The local server did not receive a response from an authoritative server. Try again later. |
| NO_RECOVERY | An unrecoverable error occurred. |
| NO_ADDRESS | The requested Name is valid but does not have an Internet address at the name server. |
| SERVICE_UNAVAILABLE | None of the name services specified are running or available. |
| EINVAL | The hostent pointer is NULL. |
| /etc/hosts | Contains the host name data base. |
| /etc/resolv.conf | Contains the name server and domain name. |
| /etc/netsvc.conf | Contains the name services ordering. |
| /usr/include/netdb.h | Contains the network database structure. |
endhostent_r Subroutine, gethostbyaddr_r Subroutine, gethostent_r Subroutine, and sethostent_r Subroutine.