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#include

Datatype Description

int8_t

uint8_t

int16_t

uint16_t

int32_t

uint32_t

Signed 8-bit integer

Unsigned 8-bit integer

Signed 16-bit integer

Unsigned 16-bit integer

Signed 32-bit integer

Unsigned 32-bit integer

sa_family_t

socklen_t

Address family of socket address structure

Length of socket address structure, normally

uint32_t

in_addr_t

in_port_t

IPv4 address, normally uint32_t

TCP or UDP port, normally uint16_t

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Byte Ordering

16-bit integer is made up of 2 bytes. 2 ways

to store the bytes in memory

Little-endian byte order: low order byte at

the beginning address

Big-endian byte order: high-order byte at

the starting address

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Network byte order and host byte

order TCP/IP specifies a standard representation

for binary integers used in protocol headers

called Network byte order that representsintegers with the most significant byte first

We refer to the byte ordering used by given

system as the host byte order

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Byte-ordering functions

Following function converts integers

htons--from host to network byte order short

unit16_t htons(unit16_t value); ntohs--from network to host byte order short

unit16_t ntohs(unit16_t value);

htonlfrom host to network byte order long

unit32_t htonl(unit32_t value);

ntohs--from network to host byte order longunit32_t ntohl(unit32_t value);

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bzero function

Syntax

void bzero( void *dest, size_t nbytes);

It is provided by most the system to set nbytes ofmemory pointed by dest as 0.

Example

bzero( &servaddr, sizeof(servaddr)); Will set servaddr ( server address struct) as 0

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Group of address conversion

functionsint inet_aton( const char *strptr, struct in_addr *addrptr);

Returns; 1 if string was valid, 0 on error

convert from ASCII string to network byte order binaryvalues

char * inet_ntoa( struct inaddr inaddr);

Return: pointer to dotted-decimal string

Convert from network byte order binary value to dotteddecimal string

These two functions convert IPv4 address

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int inet_pton( int family, constchar* strptr, void *addrptr);

Function will convert IP address in string(strptr) to the numeric value as in address

struct( addptr).

Return 1 if OK, return1 on error

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Const char *inet_ntop(int family,const void *addptr, char *strptr,size_t len);

return pointer if K, NULL on error

Does the reverse conversion, from numeric(addptr) to presentation (strptr). The len is

the size of the destination, to prevent thefunction from overflowing the callersbuffer.

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