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 .