Liaisons par trames

Description détaillée

Ce module fournit des fonctions permettant des gérer les liaisons par trames avec contrôle d'erreur.
Les messages ont le format suivant:
<SOH><STX>[Data Hexa ASCII]<ETX>[CRC CCITT Hexa ASCII]<EOT>

Graphe de collaboration de Liaisons par trames:

Fonctions
int	iTncError (struct xTnc *tnc)
int	iTncPoll (struct xTnc *tnc)
ssize_t	iTncWrite (struct xTnc *tnc, const void *buf, size_t count)
void	vTncClear (struct xTnc *p)
void	vTncInit (struct xTnc *p, FILE *fin, FILE *fout)

Macros
#define	TNC_CRC   6
#define	TNC_EOT   4
#define	TNC_ETX   3
#define	TNC_SOH   1
#define	TNC_STX   2
#define	TNC_TXT   5

Énumérations
enum	eTncError {   TNC_SUCCESS = 0, TNC_CRC_ERROR = -1, TNC_NOT_ENOUGH_MEMORY = -2, TNC_OBJECT_NOT_FOUND = -3,   TNC_ILLEGAL_MSG = -4, TNC_FILE_NOT_FOUND = -5, TNC_IO_ERROR = -6 }

Documentation du type de l'énumération

enum eTncError

List of error codes returned by the functions.

Définition à la ligne 60 du fichier tnc.h.

             {

  TNC_SUCCESS                  =  0,
  TNC_CRC_ERROR                = -1,
  TNC_NOT_ENOUGH_MEMORY        = -2,
  TNC_OBJECT_NOT_FOUND         = -3,
  TNC_ILLEGAL_MSG              = -4,
  TNC_FILE_NOT_FOUND           = -5,
  TNC_IO_ERROR                 = -6

} eTncError;

Documentation des fonctions

int iTncError

(

struct xTnc *

tnc

)

Retruns the last error code.

int iTncPoll

(

struct xTnc *

tnc

)

Check if there are any TNC messages to be processed. This function read available characters from the medium and search for any TNC messages. If a message is found, this function return true and the message can be read with iTncRead(). This function may be blocking if there are no available chars and the FILE used in tnc to access the medium is configured in blocking mode.

Paramètres

tnc	TNC object to operate on.

Renvoie

true if , negative value on error

Exemples:

net/tnc/master/demo_tnc_master.c, et net/tnc/slave/demo_tnc_slave.c.

ssize_t iTncWrite	(	struct xTnc *	tnc,
		const void *	buf,
		size_t	count
	)

Send an TNC message

Paramètres

tnc	TNC object to operate on.
frame	message to send

Renvoie

TNC_SUCCESS, negative value on error

Exemples:

net/tnc/master/demo_tnc_master.c, et net/tnc/slave/demo_tnc_slave.c.

void vTncClear

(

struct xTnc *

p

)

Clear all fields of the object

void vTncInit	(	struct xTnc *	p,
		FILE *	fin,
		FILE *	fout
	)

Create and initialize a new xTnc object

This object should be deleted with vTncDelete()

Renvoie

pointer on the object, NULL on error

Exemples:

net/tnc/master/demo_tnc_master.c, et net/tnc/slave/demo_tnc_slave.c.