inet_ntop(3)

1inet_ntop(3)               Library Functions Manual               inet_ntop(3)
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NAME

6       inet_ntop - convert IPv4 and IPv6 addresses from binary to text form
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LIBRARY

9       Standard C library (libc, -lc)
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SYNOPSIS

12       #include <arpa/inet.h>
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14       const char *inet_ntop(int af, const void *restrict src,
15                             char dst[restrict .size], socklen_t size);
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DESCRIPTION

18       This  function converts the network address structure src in the af ad‐
19       dress family into a character string.  The resulting string  is  copied
20       to the buffer pointed to by dst, which must be a non-null pointer.  The
21       caller specifies the number of bytes available in this  buffer  in  the
22       argument size.
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24       inet_ntop()  extends  the inet_ntoa(3) function to support multiple ad‐
25       dress families, inet_ntoa(3) is now considered to be deprecated in  fa‐
26       vor  of inet_ntop().  The following address families are currently sup‐
27       ported:
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29       AF_INET
30              src points to a struct in_addr (in network byte order) which  is
31              converted  to an IPv4 network address in the dotted-decimal for‐
32              mat,  "ddd.ddd.ddd.ddd".   The  buffer  dst  must  be  at  least
33              INET_ADDRSTRLEN bytes long.
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35       AF_INET6
36              src points to a struct in6_addr (in network byte order) which is
37              converted to a representation of this address in the most appro‐
38              priate IPv6 network address format for this address.  The buffer
39              dst must be at least INET6_ADDRSTRLEN bytes long.
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RETURN VALUE

42       On success, inet_ntop() returns a non-null pointer to dst.  NULL is re‐
43       turned if there was an error, with errno set to indicate the error.
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ERRORS

46       EAFNOSUPPORT
47              af was not a valid address family.
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49       ENOSPC The  converted  address  string  would  exceed the size given by
50              size.
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ATTRIBUTES

53       For an  explanation  of  the  terms  used  in  this  section,  see  at‐
54       tributes(7).
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56       ┌─────────────────────────────────────┬───────────────┬────────────────┐
57       │Interface                            │ Attribute     │ Value          │
58       ├─────────────────────────────────────┼───────────────┼────────────────┤
59       │inet_ntop()                          │ Thread safety │ MT-Safe locale │
60       └─────────────────────────────────────┴───────────────┴────────────────┘
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STANDARDS

63       POSIX.1-2008.
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HISTORY

66       POSIX.1-2001.
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68       Note  that RFC 2553 defines a prototype where the last argument size is
69       of type size_t.  Many systems follow RFC 2553.  glibc 2.0 and 2.1  have
70       size_t, but 2.2 and later have socklen_t.
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BUGS

73       AF_INET6 converts IPv4-mapped IPv6 addresses into an IPv6 format.
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EXAMPLES

76       See inet_pton(3).
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