getprotobynumber

getprotobynumber

Gets Protocol Information by Number

Portability: UNIX compatible

SYNOPSIS
DESCRIPTION
RETURN VALUE
CAUTION
PORTABILITY
IMPLEMENTATION
RELATED FUNCTIONS

SYNOPSIS

#include <netdb.h>

struct protoent *getprotobynumber(int proto);

DESCRIPTION

Given the number of a protocol, specified by proto , getprotobynumber returns a pointer to the protoent structure defined in <netdb.h> for the specified network protocol proto . Refer to <netdb.h> for details on the protoent structure. This structure is typically used to obtain the name of the protocol from the p_name field. The source of the data in this structure is the protocols file, that is, a file with the same format as the /etc/protocols file on a UNIX operating system.

Refer to Search Logic for information on the logic used to determine the location of the protocols file.

RETURN VALUE

If getprotobynumber succeeds, it returns a pointer to the protoent structure. A null pointer indicates the network address was not found in the network file.

CAUTION

The value that getprotobynumber returns points to a static structure within the library. You must copy the information from this structure before you make further getprotobyname , getprotobynumber , or getprotoent calls.

PORTABILITY

getprotobynumber is portable to other environments, including most UNIX systems, that implement BSD sockets.

IMPLEMENTATION

getprotobynumber is ported directly from the BSD UNIX Socket Library.

RELATED FUNCTIONS

endprotoent , setprotoent , getprotobyname , getprotoent

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