#include <netdb.h> struct protoent *getprotoent(void); struct protoent *getprotobyname(const char *name); struct protoent *getprotobynumber(int proto); void setprotoent(int stayopen); void endprotoent(void);
The getprotobyname() function returns a protoent structure for the entry from the database that matches the protocol name name. A connection is opened to the database if necessary.
The getprotobynumber() function returns a protoent structure for the entry from the database that matches the protocol number number. A connection is opened to the database if necessary.
The setprotoent() 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 getproto*() functions.
The endprotoent() function closes the connection to the database.
The protoent structure is defined in <netdb.h> as follows:
struct protoent {
char *p_name; /* official protocol name */
char **p_aliases; /* alias list */
int p_proto; /* protocol number */
}
The members of the protoent structure are:
| Interface | Attribute | Value |
| getprotoent() | Thread safety |
MT-Unsafe race:protoent
race:protoentbuf locale |
| getprotobyname() | Thread safety |
MT-Unsafe race:protobyname
locale |
| getprotobynumber() | Thread safety |
MT-Unsafe race:protobynumber
locale |
|
setprotoent(),
endprotoent() | Thread safety |
MT-Unsafe race:protoent
locale |
In the above table, protoent in race:protoent signifies that if any of the functions setprotoent(), getprotoent(), or endprotoent() are used in parallel in different threads of a program, then data races could occur.