phd_connect.c

本例利用C MEX及API文件实现matlab与PHD只见的通讯.能实现数据的存取。

/*
Program to login into PHD
PHD = Process History database, a Honeywell-database to store chemical plant data

Author : Hans Vereecken
BASF Antwerp
003235613411
[e-mail]

Can be distributed freely.


To compile in matlab via "mex phd_connect.c netapishr.lib"
netapishr.lib is the PHD library, found under c:\program files\...
put it in the same directory as the c-file, together with all the needed headers

*/

#include "PHDUSER.H" /* PHD-header ; has to be on your harddisk */ 
#include "mex.h" /* Matlab header */
#include <stdio.h>
#include <string.h>

void mexFunction(int nlhs,mxArray *plhs[],int nrhs,const mxArray *prhs[])
/*	Calling convention of Matlab
	nlhs : number of left hand side arguments (3 in this case)
	plhs : pointer to the left hand side arguments
	nrhs : number of right hand side arguments (0 in this case)
	plhs : pointer to the right hand side arguments



USAGE IN MATLAB : PHD_connect(host,user,pswrd);
host, user and pswrd are strings

*/

{
int   buflen; 
char *input_hostname; 
char *input_username;
char *input_password;

ISTAT status; /* defined in PHDUSER.H */


/*------------------------------------------------------------------------------------------*/

/* Error checking 
   number of arguments */
    if(nrhs!=3) 
      mexErrMsgTxt("3 inputs required.");
    else if(nlhs > 0) 
      mexErrMsgTxt("Too many output arguments.");

/* First input must be a string (the host-id) */
    if ( mxIsChar(prhs[0]) != 1)
      mexErrMsgTxt("First input must be a string.");

/* First input must be a row vector */
    if (mxGetM(prhs[0])!=1)
      mexErrMsgTxt("First input must be a row vector.");
    
/* get the length of the first input string */
    buflen = (mxGetM(prhs[0]) * mxGetN(prhs[0])) + 1;
/* allocate memory for first input string */
    input_hostname=mxCalloc(buflen, sizeof(char));

/* copy the string data from prhs[0] into a C string.*/
    status = mxGetString(prhs[0], input_hostname, buflen);
    if(status != 0) 
      mexWarnMsgTxt("Not enough space. First string is truncated.");

status=phd_sethost(input_hostname); /* sethostname ; PHD API routine */
mxFree(input_hostname); /* Free the memory*/

if(status!=0)
	{
	mexPrintf("Can not connect to host!\n");
	return;
	}

/*-------------------------------------------------------------------------*/

/* Second input must be a string (the user-id) */
    if ( mxIsChar(prhs[1]) != 1)
      mexErrMsgTxt("Second input must be a string.");

/* Second input must be a row vector */
    if (mxGetM(prhs[1])!=1)
      mexErrMsgTxt("Second input must be a row vector.");
    
/* Get the length of the second input string */
    buflen = (mxGetM(prhs[1]) * mxGetN(prhs[1])) + 1;

/* allocate memory for input string */
    input_username=mxCalloc(buflen, sizeof(char));

/* copy the string data from prhs[1] into a C string.*/
    status = mxGetString(prhs[1], input_username, buflen);
    if(status != 0) 
      mexWarnMsgTxt("Not enough space. Second string (username) is truncated.");

/* Third input must be a string (the password) */
    if ( mxIsChar(prhs[2]) != 1)
      mexErrMsgTxt("The third input (the password) must be a string.");

/* Third input must be a row vector */
    if (mxGetM(prhs[2])!=1)
      mexErrMsgTxt("Third input must be a row vector.");
    
/* Get the length of the third input string */
    buflen = (mxGetM(prhs[2]) * mxGetN(prhs[2])) + 1;

/* allocate memory for input string */
    input_password=mxCalloc(buflen, sizeof(char));

/* copy the string data from prhs[2] into a C string.*/
    status = mxGetString(prhs[2], input_password, buflen);
    if(status != 0) 
      mexWarnMsgTxt("Not enough space. third string (the password) is truncated.");

status=phd_login(input_username,input_password);
if(status!=0)
	{
	mexPrintf("Can not login to host. Wrong user/password!\n");
	return;
	}

mxFree(input_username); /* Free the memory*/
mxFree(input_password); /* Free the memory*/

/* End of login procedure */

}