angående headers (.h)

[mikal1]

Hvordan finner jeg for eksempel ut hvilken headers jeg trenger til å utføre en oppgave... (et eksempel): hvist jeg skulle lage et internet program, hvordan kunne jeg da vite at det var winsocked.h jeg skulle bruke.. OG ikke minst hvordan det fungerte?

[lodott]

Antar at du må lese dokumentasjonen som tilhører h.filene. Evt kan du jo spørre om hjelp her, så kan folk fortelle deg hvilke headers du må inkludere for at du skal få programmet til å fungere.

[Orjanp]

Er det ikke bare å prøve å kompilere så finner du ut hvilke funksjoner som er ukjent. Dermed er det bare å sjekke man file(linux) eller på nettet hvilken .h fil du trenger.

[Rafael]

Jeg har hvertfall lest litt om forskjellige headers og deres funksjoner på nettet. En

del som er tilgjengelig.

[søppel]

Enkelt (men alikevell vanskelig?). Du må skaffe deg et ordforåd, slå opp og finn sammenhenger. Handler mest om en måte å tenke på. Som utgangspunkt kan du bruke de mange resursene som er nevnt i tråder tidligere her.

 

Snarveien er som oftest en bok, selv om det noen ganger ikke virker slik .. "800 sider!? omg ..."

 

Si du har funnet ut at du må bruke funksjonen socket(), da står det beskrevet i bunnen av dette oppslagsverket hvilke headere du må inkludere og hvilke biblioteker du må linke med:

http://msdn.microsoft.com/library/en-us/wi....asp?frame=true

 

Tilsvarende under *nix skriver man "man socket" og får frem:

SOCKET(2)                                              Linux Programmer's Manual                                              SOCKET(2)

 

 

 

NAME

      socket - create an endpoint for communication

 

SYNOPSIS

      #include <sys/types.h>

      #include <sys/socket.h>

 

      int socket(int domain, int type, int protocol);

 

DESCRIPTION

      Socket creates an endpoint for communication and returns a descriptor.

 

      The  domain  parameter  specifies  a communication domain; this selects the protocol family which will be used for communication.

      These families are defined in <sys/socket.h>.  The currently understood formats include:

 

 

      Name                Purpose                          Man page

      PF_UNIX, PF_LOCAL  Local communication              unix(7)

      PF_INET            IPv4 Internet protocols          ip(7)

      PF_INET6            IPv6 Internet protocols

      PF_IPX              IPX - Novell protocols

      PF_NETLINK          Kernel user interface device    netlink(7)

      PF_X25              ITU-T X.25 / ISO-8208 protocol  x25(7)

      PF_AX25            Amateur radio AX.25 protocol

      PF_ATMPVC          Access to raw ATM PVCs

      PF_APPLETALK        Appletalk                        ddp(7)

      PF_PACKET          Low level packet interface      packet(7)

 

      The socket has the indicated type, which specifies the communication semantics.  Currently defined types are:

 

      SOCK_STREAM

              Provides sequenced, reliable, two-way, connection-based byte streams.  An out-of-band data transmission mechanism  may  be

              supported.

 

      SOCK_DGRAM

              Supports datagrams (connectionless, unreliable messages of a fixed maximum length).

 

      SOCK_SEQPACKET

              Provides  a  sequenced, reliable, two-way connection-based data transmission path for datagrams of fixed maximum length; a

              consumer is required to read an entire packet with each read system call.

 

      SOCK_RAW

              Provides raw network protocol access.

 

      SOCK_RDM

              Provides a reliable datagram layer that does not guarantee ordering.

 

      SOCK_PACKET

              Obsolete and should not be used in new programs; see packet(7).

 

      Some socket types may not be implemented by all protocol families; for example, SOCK_SEQPACKET is not implemented for AF_INET.

 

      The protocol specifies a particular protocol to be used with the socket.  Normally only a single protocol  exists  to  support  a

      particular  socket  type within a given protocol family, in which a case protocol can be specified as 0.  However, it is possible

      that many protocols may exist, in which case a particular protocol must be specified in this manner.  The protocol number to  use

      is  specific  to the "communication domain" in which communication is to take place; see protocols(5).  See getprotoent(3) on how

      to map protocol name strings to protocol numbers.

 

      Sockets of type SOCK_STREAM are full-duplex byte streams, similar to pipes.  They do not preserve  record  boundaries.  A  stream

      socket  must  be  in  a connected state before any data may be sent or received on it.  A connection to another socket is created

      with a connect(2) call.  Once connected, data may be transferred using read(2) and write(2) calls or some variant of the  send(2)

      and  recv(2)  calls.  When a session has been completed a close(2) may be performed.  Out-of-band data may also be transmitted as

      described in send(2) and received as described in recv(2).

 

      The communications protocols which implement a SOCK_STREAM ensure that data is not lost or duplicated.  If a piece  of  data  for

      which  the peer protocol has buffer space cannot be successfully transmitted within a reasonable length of time, then the connec-

      tion is considered to be dead.  When SO_KEEPALIVE is enabled on the socket the protocol checks in a protocol-specific  manner  if

      the  other  end  is still alive.  A SIGPIPE signal is raised if a process sends or receives on a broken stream; this causes naive

      processes, which do not handle the signal, to exit.  SOCK_SEQPACKET sockets employ the same system calls as SOCK_STREAM  sockets.

      The only difference is that read(2) calls will return only the amount of data requested, and any remaining in the arriving packet

      will be discarded. Also all message boundaries in incoming datagrams are preserved.

 

      SOCK_DGRAM and SOCK_RAW sockets allow sending of datagrams to correspondents named in send(2)  calls.  Datagrams  are  generally

      received with recvfrom(2), which returns the next datagram with its return address.

 

      SOCK_PACKET is an obsolete socket type to receive raw packets directly from the device driver. Use packet(7) instead.

 

      An  fcntl(2)  call with the the F_SETOWN argument can be used to specify a process group to receive a SIGURG signal when the out-

      of-band data arrives or SIGPIPE signal when a SOCK_STREAM connection breaks unexpectedly.  It may also be used to set the process

      or process group that receives the I/O and asynchronous notification of I/O events via SIGIO.  Using F_SETOWN is equivalent to an

      ioctl(2) call with the FIOSETOWN or SIOCSPGRP argument.

 

      When the network signals an error condition to the protocol module (e.g.  using a ICMP message for IP) the pending error flag  is

      set  for the socket.  The next operation on this socket will return the error code of the pending error. For some protocols it is

      possible to enable a per-socket error queue to retrieve detailed information about the error; see IP_RECVERR in ip(7).

 

      The operation of sockets is controlled by socket level options.  These options are defined in <sys/socket.h>.  The functions set-

      sockopt(2) and getsockopt(2) are used to set and get options, respectively.

 

RETURN VALUE

      -1 is returned if an error occurs; otherwise the return value is a descriptor referencing the socket.

 

ERRORS

      EACCES Permission to create a socket of the specified type and/or protocol is denied.

 

      EAFNOSUPPORT

              The implementation does not support the specified address family.

 

      EINVAL Unknown protocol, or protocol family not available.

 

      EMFILE Process file table overflow.

 

      ENFILE The system limit on the total number of open files has been reached.

 

      ENOBUFS or ENOMEM

              Insufficient memory is available.  The socket cannot be created until sufficient resources are freed.

 

      EPROTONOSUPPORT

              The protocol type or the specified protocol is not supported within this domain.

 

      Other errors may be generated by the underlying protocol modules.

 

CONFORMING TO

      4.4BSD,  SUSv2, POSIX 1003.1-2001.  The socket function call appeared in 4.2BSD. It is generally portable to/from non-BSD systems

      supporting clones of the BSD socket layer (including System V variants).

 

NOTE

      The manifest constants used under BSD 4.* for protocol families are PF_UNIX, PF_INET, etc.,  while  AF_UNIX  etc.  are  used  for

      address  families. However, already the BSD man page promises: "The protocol family generally is the same as the address family",

      and subsequent standards use AF_* everywhere.

 

BUGS

      SOCK_UUCP is not implemented yet.

 

SEE ALSO

      accept(2), bind(2), connect(2), fcntl(2), getpeername(2), getsockname(2), getsockopt(2), ioctl(2), listen(2),  read(2),  recv(2),

      select(2), send(2), shutdown(2), socketpair(2), write(2), getprotoent(3), ip(7), socket(7), tcp(7), udp(7), unix(7)

 

      "An Introductory 4.3 BSD Interprocess Communication Tutorial" is reprinted in UNIX Programmer's Supplementary Documents Volume 1.

 

      "BSD Interprocess Communication Tutorial" is reprinted in UNIX Programmer's Supplementary Documents Volume 1.

 

 

 

Linux 2.6.7                                                    2004-06-17                                                      SOCKET(2)

Endret 3. desember 2004 av søppel