#include <netdb.h> struct servent *getservent(void); struct servent *getservbyname(const char *name, const char *proto); struct servent *getservbyport(int port, const char *proto); void setservent(int stayopen); void endservent(void);
The getservbyname() function returns a servent structure for the entry from the database that matches the service name using protocol proto. If proto is NULL, any protocol will be matched. A connection is opened to the database if necessary.
The getservbyport() function returns a servent structure for the entry from the database that matches the port port (given in network byte order) using protocol proto. If proto is NULL, any protocol will be matched. A connection is opened to the database if necessary.
The setservent() function opens a connection to the database, and sets the next entry to the first entry. If stayopen is nonzero, then the connection to the database will not be closed between calls to one of the getserv*() functions.
The endservent() function closes the connection to the database.
The servent structure is defined in <netdb.h> as follows:
struct servent {
char *s_name; /* official service name */
char **s_aliases; /* alias list */
int s_port; /* port number */
char *s_proto; /* protocol to use */
}
The members of the servent structure are:
| Interface | Attribute | Value |
| getservent() | Thread safety |
MT-Unsafe race:servent
race:serventbuf locale
|
| getservbyname() | Thread safety |
MT-Unsafe race:servbyname
locale
|
| getservbyport() | Thread safety |
MT-Unsafe race:servbyport
locale
|
| setservent(), endservent() | Thread safety |
MT-Unsafe race:servent
locale
|
In the above table, servent in race:servent signifies that if any of the functions setservent(), getservent(), or endservent() are used in parallel in different threads of a program, then data races could occur.