gen.subproj/getprotoent.3

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  28 .\"     @(#)getprotoent.3       8.1 (Berkeley) 6/4/93
  29 .\" $FreeBSD: src/lib/libc/net/getprotoent.3,v 1.12 2007/01/09 00:28:02 imp Exp $
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  31 .Dd June 4, 1993
  32 .Dt GETPROTOENT 3
  33 .Os
  34 .Sh NAME
  35 .Nm getprotoent ,
  36 .Nm getprotobynumber ,
  37 .Nm getprotobyname ,
  38 .Nm setprotoent ,
  39 .Nm endprotoent
  40 .Nd get protocol entry
  41 .Sh LIBRARY
  42 .Lb libc
  43 .Sh SYNOPSIS
  44 .In netdb.h
  45 .Ft struct protoent *
  46 .Fn getprotoent void
  47 .Ft struct protoent *
  48 .Fn getprotobyname "const char *name"
  49 .Ft struct protoent *
  50 .Fn getprotobynumber "int proto"
  51 .Ft void
  52 .Fn setprotoent "int stayopen"
  53 .Ft void
  54 .Fn endprotoent void
  55 .Sh DESCRIPTION
  56 The
  57 .Fn getprotoent ,
  58 .Fn getprotobyname ,
  59 and
  60 .Fn getprotobynumber
  61 functions
  62 each return a pointer to an object with the
  63 following structure
  64 containing the broken-out
  65 fields of a line in the network protocol data base,
  66 .Pa /etc/protocols .
  67 .Pp
  68 .Bd -literal -offset indent
  69 struct  protoent {
  70         char    *p_name;        /* official name of protocol */
  71         char    **p_aliases;    /* alias list */
  72         int     p_proto;        /* protocol number */
  73 };
  74 .Ed
  75 .Pp
  76 The members of this structure are:
  77 .Bl -tag -width p_aliases
  78 .It Fa p_name
  79 The official name of the protocol.
  80 .It Fa p_aliases
  81 A zero terminated list of alternate names for the protocol.
  82 .It Fa p_proto
  83 The protocol number.
  84 .El
  85 .Pp
  86 The
  87 .Fn getprotoent
  88 function
  89 reads the next line of the file, opening the file if necessary.
  90 .Pp
  91 The
  92 .Fn setprotoent
  93 function
  94 opens and rewinds the file.
  95 If the
  96 .Fa stayopen
  97 flag is non-zero,
  98 the net data base will not be closed after each call to
  99 .Fn getprotobyname
 100 or
 101 .Fn getprotobynumber .
 102 .Pp
 103 The
 104 .Fn endprotoent
 105 function
 106 closes the file.
 107 .Pp
 108 The
 109 .Fn getprotobyname
 110 function
 111 and
 112 .Fn getprotobynumber
 113 sequentially search from the beginning
 114 of the file until a matching
 115 protocol name or
 116 protocol number is found,
 117 or until
 118 .Dv EOF
 119 is encountered.
 120 .Sh RETURN VALUES
 121 Null pointer
 122 (0) returned on
 123 .Dv EOF
 124 or error.
 125 .Sh FILES
 126 .Bl -tag -width /etc/protocols -compact
 127 .It Pa /etc/protocols
 128 .El
 129 .Sh SEE ALSO
 130 .Xr protocols 5
 131 .Sh HISTORY
 132 The
 133 .Fn getprotoent ,
 134 .Fn getprotobynumber ,
 135 .Fn getprotobyname ,
 136 .Fn setprotoent ,
 137 and
 138 .Fn endprotoent
 139 functions appeared in
 140 .Bx 4.2 .
 141 .Sh BUGS
 142 These functions use a thread-specific data space;
 143 if the data is needed for future use, it should be
 144 copied before any subsequent calls overwrite it.
 145 Only the Internet
 146 protocols are currently understood.