netdb.h(3head)

1netdb.h(3HEAD)                      Headers                     netdb.h(3HEAD)
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NAME

6       netdb.h, netdb - definitions for network database operations
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SYNOPSIS

9       #include <netdb.h>
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DESCRIPTION

13       The  <netdb.h> header defines the type in_port_t and the type in_addr_t
14       as described in in.h(3HEAD).
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17       The <netdb.h> header defines the hostent structure  that  includes  the
18       following members:
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20         char *h_name          /* official name of the host */
21         char **h_aliases      /* pointer to an array of pointers to
22                                  alternative host names, terminated
23                                  by a null pointer */
24         int  h_addrtype       /* address type */
25         int  h_length         /* length, in bytes, of the address */
26         char **h_addr_list    /* pointer to an array of pointers to
27                                  network addresses (in network byte
28                                  order)for the host, terminated by a
29                                  null pointer */
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33       The  <netdb.h>  header  defines  the netent structure that includes the
34       following members:
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36         char      *n_name     /* official, fully-qualified */
37                                  (including the domain) name
38                                  of the network */
39         char      **n_aliases /* pointer to an array of pointers to
40                                  alternative network names, terminated */
41                                  by a null pointer */
42         int       n_addrtype  /* the address type of the network */
43         in_addr_t n_net       /* the network number, in host byte order */
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47       The <netdb.h> header defines the protoent structure that  includes  the
48       following members:
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50         char *p_name         /* official name of the protocol */
51         char **p_aliases     /* pointer to an array of pointers to
52                                 alternative protocol names, terminated
53                                 by a null pointer */
54         int  p_proto         /* protocol number */
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58       The  <netdb.h>  header  defines the servent structure that includes the
59       following members:
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61         char *s_name         /* oficial name of the service */
62         char **s_aliases     /* pointer to an array of pointers to
63                                 alternativeservice names, terminated by
64                                 a null pointer */
65         int  s_port          /* port number at which the service
66                                 resides, in network byte order */
67         char *s_proto        /* name of the protocol to use when
68                                 contacting the service */
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72       The <netdb.h> header defines the macro IPPORT_RESERVED with  the  value
73       of the highest reserved Internet port number.
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76       The <netdb.h> header provides a declaration for h_errno:
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79       extern int h_errno;
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82       The <netdb.h> header defines the following macros for use as error val‐
83       ues for gethostbyaddr() and gethostbyname():
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88       HOST_NOT_FOUND      NO_DATA
89       NO_RECOVERY         TRY_AGAIN
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93       Inclusion of the <netdb.h> header may also  make  visible  all  symbols
94       from in.h(3HEAD).
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ATTRIBUTES

97       See attributes(5) for descriptions of the following attributes:
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102       ┌─────────────────────────────┬─────────────────────────────┐
103       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
104       ├─────────────────────────────┼─────────────────────────────┤
105       │Interface Stability          │Standard                     │
106       └─────────────────────────────┴─────────────────────────────┘
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NAME

SYNOPSIS

DESCRIPTION

ATTRIBUTES

SEE ALSO