NAME

getservent, getservbyport, getservbyname, setservent, endservent − get service entry

SYNOPSIS

#include <netdb.h>

struct servent ∗getservent()

struct servent ∗getservbyname(name, proto)
char ∗name, ∗proto;

struct servent ∗getservbyport(port, proto)
int port; char ∗proto;

setservent(stayopen)
int stayopen

endservent()

DESCRIPTION

getservent, getservbyname, and getservbyport each return a pointer to an object with the following structure containing the broken-out fields of a line in the network services data base, /etc/services. 

structservent {
char∗s_name;/∗ official name of service ∗/
char∗∗s_aliases;/∗ alias list ∗/
longs_port;/∗ port service resides at ∗/
char∗s_proto;/∗ protocol to use ∗/
};

The members of this structure are:

s_name The official name of the service. 

s_aliases A zero terminated list of alternate names for the service. 

s_port The port number at which the service resides.  Port numbers are returned in network byte order. 

s_proto The name of the protocol to use when contacting the service. 

CX supports both a proprietary version and an 88open Object Compatibility Standard Networking Supplement (OCSNS) version of getservbyname and getservbyport.  The OCSNS versions of these functions check for the existence of the function /etc/bcs_cat and if it exists and has proper execute permission, will issue a popen(3S) call of the command /etc/bcs_cat services.  If the file does not exist, the functions will access the /etc/services file. 

getservent reads the next line of the file /etc/services, opening the file if necessary and returning a pointer to a servent structure containing the file entry. 

Setservent opens and rewinds the file /etc/services.  If the stayopen flag is non-zero, the net data base will not be closed after each call to getservent, getservbyname, or getservbyport. 

Endservent closes the file /etc/services and clears the stayopen flag. 

The functions getservent, setservent, and endservent are defined in the 88open OCSNS.  Their functionality is the same as described above. 

Both versions of getservbyname and getservbyport sequentially search from the beginning of the file until a matching protocol name or port number is found, or until EOF is encountered.  If a protocol name is also supplied (non-NULL), searches must also match the protocol. 

NOTE

The OCSNS versions of the above files may be accessed through special OCS options passed to cc(1) and/or ld(1). 

FILES

/etc/services

SEE ALSO

bcs_cat(1), getprotoent(3N), services(4C)

DIAGNOSTICS

Null pointer (0) returned on EOF or error. 

BUGS

All information is contained in a static area so it must be copied if it is to be saved.  Expecting port numbers to fit in a 32 bit quantity is probably naive. 

CX/UX Networking