Name

getprotoent, getprotobyname, getprotobynumber, setprotoent, endprotoent — get protocol entry

Synopsis

#include <netdb.h>
struct protoent *getprotoent( void);  
struct protoent *getprotobyname( const char *  name);
struct protoent *getprotobynumber( int   proto);
void setprotoent( int   stayopen);
void endprotoent( void);  

DESCRIPTION

The getprotoent() function reads the next line from the file /etc/protocols and returns a structure protoent containing the broken out fields from the line. The /etc/protocols file is opened if necessary.

The getprotobyname() function returns a protoent structure for the line from /etc/protocols that matches the protocol name name.

The getprotobynumber() function returns a protoent structure for the line that matches the protocol number number.

The setprotoent() function opens and rewinds the /etc/protocols file. If stayopen is true (1), then the file will not be closed between calls to getprotobyname() or getprotobynumber().

The endprotoent() function closes /etc/protocols.

The protoent structure is defined in <netdb.h> as follows:

struct protoent {
  char * p_name;
/* official protocol name */
  char ** p_aliases;
/* alias list */
  int   p_proto;
/* protocol number */
};

The members of the protoent structure are:

p_name

The official name of the protocol.

p_aliases

A zero terminated list of alternative names for the protocol.

p_proto

The protocol number.

RETURN VALUE

The getprotoent(), getprotobyname() and getprotobynumber() functions return the protoent structure, or a NULL pointer if an error occurs or the end of the file is reached.

FILES

/etc/protocols

protocol database file

CONFORMING TO

4.3BSD, POSIX.1-2001.

SEE ALSO

getnetent(3), getservent(3), protocols(5)

COLOPHON

This page is part of release 2.79 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.


  Copyright 1993 David Metcalfe (davidprism.demon.co.uk)

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References consulted:
    Linux libc source code
    Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
    386BSD man pages
Modified Sat Jul 24 19:26:03 1993 by Rik Faith (faithcs.unc.edu)