/** @file ../include/arpa/inet.h

@internalComponent

*/

/** @fn  inet_addr(const char *cp)

@param cp

Note: This description also covers the following functions -

 inet_aton()  inet_ntoa()  inet_ntop()  inet_pton() 

@code

  struct in_addr or some other internal binary representation, in network byte order).

 It returns 1 if the address was valid for the specified address family, or

 0 if the address was not parseable in the specified address family, or -1

 if some system error occurred.

 This function is presently valid for AF_INET and AF_INET6.

@endcode

@code

  struct in_addr or some other binary form, in network byte order) to presentation format

 (suitable for external display purposes).

 The size argument specifies the size, in bytes, of the buffer *dst It returns NULL if a system error occurs (in which case, errno will have been set), or it returns a pointer to the destination string.

 This function is presently valid for AF_INET and AF_INET6.

@endcode

@code

  The routines inet_addr and inet_aton interpret character strings representing

numbers expressed in the Internet standard ‘.’ notation.

@endcode

 The inet_pton function converts a presentation format address (that is, printable form

as held in a character string) to network format (usually a  struct in_addr or some other internal binary representation, in network byte order).

It returns 1 if the address was valid for the specified address family, or

0 if the address was not parseable in the specified address family, or -1

if some system error occurred.

This function is presently valid for AF_INET and AF_INET6.

 The inet_aton routine interprets the specified character string as an Internet address,

placing the address into the structure provided.

It returns 1 if the string was successfully interpreted,

or 0 if the string is invalid.

The inet_addr functions return numbers suitable for use

as Internet addresses.

 The function inet_ntop converts an address *src from network format

(usually a  struct in_addr or some other binary form, in network byte order) to presentation format

(suitable for external display purposes).

The size argument specifies the size, in bytes, of the buffer *dst It returns NULL if a system error occurs (in which case, errno will have been set), or it returns a pointer to the destination string.

This function is presently valid for AF_INET and AF_INET6.

 The routine inet_ntoa takes an Internet address and returns an ASCII string representing the address in ' . '

notation.

 All Internet addresses are returned in network

order (bytes ordered from left to right).

All network numbers and local address parts are

returned as machine byte order integer values.

Diagnostics:

 The constant INADDR_NONE is returned by inet_addr for malformed requests.

@see gethostbyname()

Examples:

@code

#include <stdio.h>

#include <arpa/inet.h>

#include <netinet/in.h>

#define IPV6ADDRSIZE 48

int main()

    {

     unsigned int nbo_value;

     char *ipaddrstring="1.2.3.4";

     char *ipaddrholdr=NULL;

     char *ipv6addrstring="8000::123:4567:89AB:CDEF";

     struct in_addr ipstruct;

     struct in6_addr ipv6struct;

     char result[IPV6ADDRSIZE];

     int err;

     int size;

     const char* error;

     nbo_value=inet_addr(ipaddrstring);

     if(nbo_value == -1)

      {

       printf("inet_addr failed0);

      }

     else

      {

       printf("inet_addr passed0);

      }

     ipstruct.s_addr=nbo_value;

     ipaddrholdr=inet_ntoa(ipstruct);

     if(ipaddrholdr==NULL)

      {

       printf("inet_ntoa failed0);

      }

     else

      {

      printf("ipaddr is %s0,ipaddrholdr);

      }

     err=inet_pton(AF_INET6,ipv6addrstring ,&ipv6struct;);

     if(err ==0  || err==-1)

     printf("inet_pton Failed0);

     else

     printf("inet_pton passed0);

     size=sizeof(result);

     error=inet_ntop(AF_INET6,&ipv6struct.s6;_addr,result,size);     

     if(error==NULL)

      {

      printf("inet_ntop failed");

      }

     else

      {

      printf("inet_ntop passed");

      }

     err=inet_aton(ipaddrstring,&ipstruct;);

     if(err==0)

     {

      printf("invalid address ");

     }

     else

      {

      printf("inet_aton passed ");

      }

     return 0;

}

Output:

inet_addr passed

ipaddr is 1.2.3.4

inet_pton passed

inet_ntop passed

inet_aton passed

@endcode

 The inet_ntop and inet_pton functions conform to -xns5.2. Note that inet_pton does not accept 1-, 2-, or 3-part dotted addresses; all four parts

must be specified and are interpreted only as decimal values.

This is a narrower input set than that accepted by inet_aton. These

functions appeared in BSD 4.2.

Bugs:

 The value INADDR_NONE (0xffffffff) is a valid broadcast address, but inet_addr cannot return that value without indicating failure.

The newer inet_aton function does not share this problem.

The problem of host byte ordering versus network byte ordering is

confusing.

The string returned by inet_ntoa resides in a static memory area. Inet_addr should return a struct in_addr. 

@publishedAll

@externallyDefinedApi

*/

/** @fn  inet_ntoa(struct in_addr in)

@param in

Refer to  inet_addr() for the documentation

@see gethostbyname()

@publishedAll

@externallyDefinedApi

*/

/** @fn  inet_ntop(  int af ,  const void *  src,   char *  dst,   socklen_t size)  

@param af

@param src

@param dst

@param size

Refer to  inet_addr() for the documentation

@see gethostbyname()

@publishedAll

@externallyDefinedApi

*/

/** @fn  inet_pton(int af, const char *  src, void *  dst)

@param af

@param src

@param dst

Refer to  inet_addr() for the documentation

@see gethostbyname()

@publishedAll

@externallyDefinedApi

*/

/** @fn  inet_aton(const char *cp, struct in_addr *pin)

@param cp

@param pin

Refer to  inet_addr() for the documentation

@see gethostbyname()

@publishedAll

@externallyDefinedApi

*/

/** @fn  htonl(uint32_t hl)

@param hl

Note: This description also covers the following functions -

 htons()  ntohl()  ntohs() 

  These routines convert 16 and 32 bit quantities between network

byte order and host byte order.

On machines which have a byte order which is the same as the network

order, routines are defined as null macros.

 These routines are most often used in conjunction with Internet

addresses and ports as returned by gethostbyname

and getservent .

@see gethostbyaddr()

@see getservent()

Bugs:

 On the VAX bytes are handled backwards from most everyone else in

the world.

@publishedAll

@externallyDefinedApi

*/

/** @fn  htons(uint16_t hs)

@param hs

Refer to  htonl() for the documentation

@see gethostbyaddr()

@see getservent()

@publishedAll

@externallyDefinedApi

*/

/** @def  ntohl

These are also declared as functions.

@publishedAll

@externallyDefinedApi

*/

/** @def  ntohs

These are also declared as functions.

@publishedAll

@externallyDefinedApi

*/

/** @def  inet_addr

These are also declared as functions.

@publishedAll

@externallyDefinedApi

*/

/** @def  inet_ntoa

These are also declared as functions.

@publishedAll

@externallyDefinedApi

*/

/** @def  inet_pton

These are also declared as functions.

@publishedAll

@externallyDefinedApi

*/

/** @def  inet_ntop

These are also declared as functions.

@publishedAll

@externallyDefinedApi

*/