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@(#)getprotoent.3 8.1 (Berkeley) 6/4/93
$FreeBSD: releng/11.0/lib/libc/net/getprotoent.3 243156 2012-11-16 15:02:35Z kevlo $
.Dd June 4, 1993 .Dt GETPROTOENT 3 .Os .Sh NAME .Nm getprotoent , .Nm getprotobynumber , .Nm getprotobyname , .Nm setprotoent , .Nm endprotoent .Nd get protocol entry .Sh LIBRARY .Lb libc .Sh SYNOPSIS n netdb.h .Ft struct protoent * .Fn getprotoent void .Ft struct protoent * .Fn getprotobyname "const char *name" .Ft struct protoent * .Fn getprotobynumber "int proto" .Ft void .Fn setprotoent "int stayopen" .Ft void .Fn endprotoent void .Sh DESCRIPTION The .Fn getprotoent , .Fn getprotobyname , and .Fn getprotobynumber functions each return a pointer to an object with the following structure containing the broken-out fields of a line in the network protocol data base,
a /etc/protocols . d -literal -offset indent struct protoent { char *p_name; /* official name of protocol */ char **p_aliases; /* alias list */ int p_proto; /* protocol number */ }; .Ed
p The members of this structure are: l -tag -width p_aliases t Fa p_name The official name of the protocol. t Fa p_aliases A zero terminated list of alternate names for the protocol. t Fa p_proto The protocol number. .El
p The .Fn getprotoent function reads the next line of the file, opening the file if necessary.
p The .Fn setprotoent function opens and rewinds the file. If the .Fa stayopen flag is non-zero, the net data base will not be closed after each call to .Fn getprotobyname or .Fn getprotobynumber .
p The .Fn endprotoent function closes the file.
p The .Fn getprotobyname function and .Fn getprotobynumber sequentially search from the beginning of the file until a matching protocol name or protocol number is found, or until .Dv EOF is encountered. .Sh RETURN VALUES Null pointer returned on .Dv EOF or error. .Sh FILES l -tag -width /etc/protocols -compact t Pa /etc/protocols .El .Sh SEE ALSO .Xr protocols 5 .Sh HISTORY The .Fn getprotoent , .Fn getprotobynumber , .Fn getprotobyname , .Fn setprotoent , and .Fn endprotoent functions appeared in x 4.2 . .Sh BUGS These functions use a thread-specific data space; if the data is needed for future use, it should be copied before any subsequent calls overwrite it. Only the Internet protocols are currently understood.