man3/getprotoent.3

   1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
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  23 .\" References consulted:
  24 .\"     Linux libc source code
  25 .\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
  26 .\"     386BSD man pages
  27 .\" Modified Sat Jul 24 19:26:03 1993 by Rik Faith (faith@cs.unc.edu)
  28 .TH GETPROTOENT 3  1993-04-24 "BSD" "Linux Programmer's Manual"
  29 .SH NAME
  30 getprotoent, getprotobyname, getprotobynumber, setprotoent,
  31 endprotoent \- get protocol entry
  32 .SH SYNOPSIS
  33 .nf
  34 .B #include <netdb.h>
  35 .sp
  36 .B struct protoent *getprotoent(void);
  37 .sp
  38 .BI "struct protoent *getprotobyname(const char *" name );
  39 .sp
  40 .BI "struct protoent *getprotobynumber(int " proto );
  41 .sp
  42 .BI "void setprotoent(int " stayopen );
  43 .sp
  44 .B void endprotoent(void);
  45 .fi
  46 .SH DESCRIPTION
  47 The
  48 .BR getprotoent ()
  49 function reads the next line from the file
  50 \fI/etc/protocols\fP and returns a structure \fIprotoent\fP
  51 containing the broken out fields from the line.
  52 The \fI/etc/protocols\fP file is opened if necessary.
  53 .PP
  54 The
  55 .BR getprotobyname ()
  56 function returns a \fIprotoent\fP
  57 structure for the line from \fI/etc/protocols\fP that matches
  58 the protocol name \fIname\fP.
  59 .PP
  60 The
  61 .BR getprotobynumber ()
  62 function returns a \fIprotoent\fP
  63 structure for the line that matches the protocol number \fInumber\fP.
  64 .PP
  65 The
  66 .BR setprotoent ()
  67 function opens and rewinds the
  68 \fI/etc/protocols\fP file.
  69 If \fIstayopen\fP is true (1), then
  70 the file will not be closed between calls to
  71 .BR getprotobyname ()
  72 or
  73 .BR getprotobynumber ().
  74 .PP
  75 The
  76 .BR endprotoent ()
  77 function closes \fI/etc/protocols\fP.
  78 .PP
  79 The \fIprotoent\fP structure is defined in \fI<netdb.h>\fP as follows:
  80 .sp
  81 .in +0.5i
  82 .nf
  83 struct protoent {
  84     char  *p_name;       /* official protocol name */
  85     char **p_aliases;    /* alias list */
  86     int    p_proto;      /* protocol number */
  87 }
  88 .fi
  89 .in -0.5i
  90 .PP
  91 The members of the \fIprotoent\fP structure are:
  92 .TP
  93 .I p_name
  94 The official name of the protocol.
  95 .TP
  96 .I p_aliases
  97 A zero terminated list of alternative names for the protocol.
  98 .TP
  99 .I p_proto
 100 The protocol number.
 101 .SH "RETURN VALUE"
 102 The
 103 .BR getprotoent (),
 104 .BR getprotobyname ()
 105 and
 106 .BR getprotobynumber ()
 107 functions return the \fIprotoent\fP structure, or a NULL pointer if an
 108 error occurs or the end of the file is reached.
 109 .SH FILES
 110 .PD 0
 111 .TP
 112 .I /etc/protocols
 113 protocol database file
 114 .PD
 115 .SH "CONFORMING TO"
 116 4.3BSD, POSIX.1-2001.
 117 .SH "SEE ALSO"
 118 .BR getnetent (3),
 119 .BR getservent (3),
 120 .BR protocols (5)