man3p/getservent.3p

   1 .\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
   2 .TH "ENDSERVENT" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
   3 .\" endservent
   4 .SH NAME
   5 endservent, getservbyname, getservbyport, getservent, setservent \-
   6 network services database functions
   7 .SH SYNOPSIS
   8 .LP
   9 \fB#include <netdb.h>
  10 .br
  11 .sp
  12 void endservent(void);
  13 .br
  14 struct servent *getservbyname(const char *\fP\fIname\fP\fB, const
  15 char *\fP\fIproto\fP\fB);
  16 .br
  17 struct servent *getservbyport(int\fP \fIport\fP\fB, const char *\fP\fIproto\fP\fB);
  18 .br
  19 struct servent *getservent(void);
  20 .br
  21 void setservent(int\fP \fIstayopen\fP\fB);
  22 .br
  23 \fP
  24 .SH DESCRIPTION
  25 .LP
  26 These functions shall retrieve information about network services.
  27 This information is considered to be stored in a database
  28 that can be accessed sequentially or randomly. The implementation
  29 of this database is unspecified.
  30 .LP
  31 The \fIsetservent\fP() function shall open a connection to the database,
  32 and set the next entry to the first entry. If the
  33 \fIstayopen\fP argument is non-zero, the \fInet\fP database shall
  34 not be closed after each call to the \fIgetservent\fP()
  35 function (either directly, or indirectly through one of the other
  36 \fIgetserv*\fP()
  37 functions), and the implementation may maintain an open file descriptor
  38 for the database.
  39 .LP
  40 The \fIgetservent\fP() function shall read the next entry of the database,
  41 opening and closing a connection to the database as
  42 necessary.
  43 .LP
  44 The \fIgetservbyname\fP() function shall search the database from
  45 the beginning and find the first entry for which the service
  46 name specified by \fIname\fP matches the \fIs_name\fP member and the
  47 protocol name specified by \fIproto\fP matches the
  48 \fIs_proto\fP member, opening and closing a connection to the database
  49 as necessary. If \fIproto\fP is a null pointer, any value
  50 of the \fIs_proto\fP member shall be matched.
  51 .LP
  52 The \fIgetservbyport\fP() function shall search the database from
  53 the beginning and find the first entry for which the port
  54 specified by \fIport\fP matches the \fIs_port\fP member and the protocol
  55 name specified by \fIproto\fP matches the
  56 \fIs_proto\fP member, opening and closing a connection to the database
  57 as necessary. If \fIproto\fP is a null pointer, any value
  58 of the \fIs_proto\fP member shall be matched. The \fIport\fP argument
  59 shall be in network byte order.
  60 .LP
  61 The \fIgetservbyname\fP(), \fIgetservbyport\fP(), and \fIgetservent\fP()
  62 functions shall each return a pointer to a
  63 \fBservent\fP structure, the members of which shall contain the fields
  64 of an entry in the network services database.
  65 .LP
  66 The \fIendservent\fP() function shall close the database, releasing
  67 any open file descriptor.
  68 .LP
  69 These functions need not be reentrant. A function that is not required
  70 to be reentrant is not required to be thread-safe.
  71 .SH RETURN VALUE
  72 .LP
  73 Upon successful completion, \fIgetservbyname\fP(), \fIgetservbyport\fP(),
  74 and \fIgetservent\fP() return a pointer to a
  75 \fBservent\fP structure if the requested entry was found, and a null
  76 pointer if the end of the database was reached or the
  77 requested entry was not found. Otherwise, a null pointer is returned.
  78 .SH ERRORS
  79 .LP
  80 No errors are defined.
  81 .LP
  82 \fIThe following sections are informative.\fP
  83 .SH EXAMPLES
  84 .LP
  85 None.
  86 .SH APPLICATION USAGE
  87 .LP
  88 The \fIport\fP argument of \fIgetservbyport\fP() need not be compatible
  89 with the port values of all address families.
  90 .LP
  91 The \fIgetservbyname\fP(), \fIgetservbyport\fP(), and \fIgetservent\fP()
  92 functions may return pointers to static data, which
  93 may be overwritten by subsequent calls to any of these functions.
  94 .SH RATIONALE
  95 .LP
  96 None.
  97 .SH FUTURE DIRECTIONS
  98 .LP
  99 None.
 100 .SH SEE ALSO
 101 .LP
 102 \fIendhostent\fP() , \fIendprotoent\fP() , \fIhtonl\fP() , \fIinet_addr\fP()
 103 , the Base Definitions volume of
 104 IEEE\ Std\ 1003.1-2001, \fI<netdb.h>\fP
 105 .SH COPYRIGHT
 106 Portions of this text are reprinted and reproduced in electronic form
 107 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
 108 -- Portable Operating System Interface (POSIX), The Open Group Base
 109 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
 110 Electrical and Electronics Engineers, Inc and The Open Group. In the
 111 event of any discrepancy between this version and the original IEEE and
 112 The Open Group Standard, the original IEEE and The Open Group Standard
 113 is the referee document. The original Standard can be obtained online at
 114 http://www.opengroup.org/unix/online.html .