Manpages - getprotoent.3

getprotoent, getprotobyname, getprotobynumber, setprotoent, endprotoent - get protocol entry

  #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 *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.

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.

/etc/protocols

protocol database file

For an explanation of the terms used in this section, see *attributes*(7).

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.

POSIX.1-2001, POSIX.1-2008, 4.3BSD.

*getnetent*(3), *getprotoent_r*(3), *getservent*(3), *protocols*(5)

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