NAME

       endservent, getservbyname, getservbyport, getservent, setservent - network services database functions

SYNOPSIS

       #include <netdb.h>

       void endservent(void);
       struct servent *getservbyname(const char *name, const char *proto);
       struct servent *getservbyport(int port, const char *proto);
       struct servent *getservent(void);
       void setservent(int stayopen);

DESCRIPTION

       These  functions shall retrieve information about network services.  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  setservent()  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 net database shall not be closed after each call to  the
       getservent() function (either directly, or indirectly through one of the other getserv*() functions), and
       the implementation may maintain an open file descriptor for the database.

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

       The  getservbyname()  function  shall search the database from the beginning and find the first entry for
       which the service name specified by name matches the s_name member and the  protocol  name  specified  by
       proto matches the s_proto member, opening and closing a connection to the database as necessary. If proto
       is a null pointer, any value of the s_proto member shall be matched.

       The getservbyport() function shall search the database from the beginning and find the  first  entry  for
       which  the  port  specified  by  port  matches the s_port member and the protocol name specified by proto
       matches the s_proto member, opening and closing a connection to the database as necessary. If proto is  a
       null  pointer,  any  value  of the s_proto member shall be matched. The port argument shall be in network
       byte order.

       The getservbyname(), getservbyport(), and getservent() functions shall each return a pointer to a servent
       structure, the members of which shall contain the fields of an entry in the network services database.

       The endservent() function shall close 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, getservbyname(), getservbyport(), and getservent()  return  a  pointer  to  a
       servent  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 port argument of getservbyport() need not be compatible with the port values of all address families.

       The getservbyname(), getservbyport(), and getservent() 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

       endhostent()   ,   endprotoent()   ,   htonl()   ,   inet_addr()   ,   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 .