gethostid()--Retrieve Host ID Address

#include <sys/types.h>
#include <sys/socket.h>

int gethostid()

The gethostid() function is used to retrieve a host ID's 32-bit IP address.

Return Value

gethostid() returns an integer. Possible values are:

• 0 when a sethostid() has not been issued previously since the last initial program load (IPL)

• n (successful), where n is the number specified on a previously issued sethostid() call

Usage Notes

1. When a process issues a sethostid(), the host_id can be accessed by any process that issues a gethostid()

2. The host_id is reset to zero when an initial program load is performed.

3. The host_id is a signed integer. Therefore, a -1 return value from the gethostid() may not indicate an error, but rather that a previous sethostid() was issued that specified a host_id of -1.

4. While many socket implementations refer to the host_id as the IP address of the machine, this is not necessarily the case. Many machines that support the TCP/IP protocol suite support multiple local IP addresses. The value contained in host_id is not used by TCP in any manner.

Related Information

• sethostid()--Set Host ID Address

• gethostname()--Retrieve Host Name

• sethostname()--Set Host Name