NAME

       endprotoent, getprotobyname, getprotobynumber, getprotoent, setprotoent - network protocol
       database functions

SYNOPSIS

       #include <netdb.h>

       void endprotoent(void);
       struct protoent *getprotobyname(const char *name);
       struct protoent *getprotobynumber(int proto);
       struct protoent *getprotoent(void);
       void setprotoent(int stayopen);

DESCRIPTION

       These functions shall retrieve information about protocols. This information is considered
       to  be  stored  in  a  database  that  can  be  accessed  sequentially  or  randomly.  The
       implementation of this database is unspecified.

       The setprotoent() function shall open a connection to the database, and set the next entry
       to  the  first  entry. If the stayopen argument is non-zero, the connection to the network
       protocol database shall not be closed after each call to getprotoent()  (either  directly,
       or  indirectly through one of the other getproto*() functions), and the implementation may
       maintain an open file descriptor for the database.

       The getprotobyname() function shall search the database from the beginning  and  find  the
       first  entry  for  which  the  protocol  name specified by name matches the p_name member,
       opening and closing a connection to the database as necessary.

       The getprotobynumber() function shall search the database from the beginning and find  the
       first  entry  for which the protocol number specified by proto matches the p_proto member,
       opening and closing a connection to the database as necessary.

       The getprotoent() function shall read the next entry of the database, opening and  closing
       a connection to the database as necessary.

       The  getprotobyname(), getprotobynumber(), and getprotoent() functions shall each return a
       pointer to a protoent structure, the members of which shall contain the fields of an entry
       in the network protocol database.

       The  endprotoent() function shall close the connection to the database, releasing any open
       file descriptor.

       These functions need not be reentrant. A function that is not required to be reentrant  is
       not required to be thread-safe.

RETURN VALUE

       Upon successful completion, getprotobyname(), getprotobynumber(), and getprotoent() return
       a pointer to a protoent structure if the requested entry was found, and a null pointer  if
       the  end  of  the  database was reached or the requested entry was not found. Otherwise, a
       null pointer is returned.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       The getprotobyname(), getprotobynumber(), and getprotoent() functions may return  pointers
       to static data, which may be overwritten by subsequent calls to any of these functions.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       The Base Definitions volume of IEEE Std 1003.1-2001, <netdb.h>

COPYRIGHT

       Portions  of  this  text  are  reprinted  and  reproduced in electronic form from IEEE Std
       1003.1, 2003 Edition, Standard for Information Technology  --  Portable  Operating  System
       Interface  (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by
       the Institute of Electrical and Electronics Engineers, Inc and  The  Open  Group.  In  the
       event  of  any  discrepancy  between this version and the original IEEE and The Open Group
       Standard, the original IEEE and The Open Group  Standard  is  the  referee  document.  The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .