getprotobyname (3)
Leading comments
Copyright 1993 David Metcalfe (david@prism.demon.co.uk) %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Sin...
NAME
getprotoent, getprotobyname, getprotobynumber, setprotoent, endprotoent - get protocol entrySYNOPSIS
#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);
DESCRIPTION
The getprotoent() function reads the next entry from the protocols database (see protocols(5)) and returns a protoent structure containing the broken-out fields from the entry. A connection is opened to the database if necessary.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:
- p_name
- The official name of the protocol.
- p_aliases
- A NULL-terminated list of alternative names for the protocol.
- p_proto
- The protocol number.
RETURN VALUE
The getprotoent(), getprotobyname() and getprotobynumber() functions return a pointer to a statically allocated protoent structure, or a null pointer if an error occurs or the end of the file is reached.FILES
- /etc/protocols
- protocol database file
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).| 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(3), getprotoent(3), or endprotoent(3) are used in parallel in different threads of a program, then data races could occur.