Create a C++ Client

This example shows how to write a MATLAB^® Production Server™ client using the C client API. The client application calls the addmatrix function you compiled in Create a Deployable Archive for MATLAB Production Server and deployed in Share a Deployable Archive on the Server Instance.

Create a C++ MATLAB Production Server client application:

Create a file called addmatrix_client.cpp.
Using a text editor, open addmatrix_client.cpp.

Add the following include statements to the file:

#include <iostream>
#include <mps/client.h>

Note: The header files for the MATLAB Production Server C client API are located in the $MPS_INSTALL/client/c/include/mps folder where $MPS_INSTALL is the root folder which MATLAB Production Server is installed.

Add the main() method to the application.
```
int main ( void )
{
} 
```

Initialize the client runtime.

mpsClientRuntime* mpsruntime = mpsInitializeEx(MPS_CLIENT_1_1);

Create the client configuration.

mpsClientConfig* config;
mpsStatus status = mpsruntime->createConfig(&config);

Create the client context.

mpsClientContext* context;
status = mpsruntime->createContext(&context, config);

Create the MATLAB data to input to the function.

double a1[2][3] = {{1,2,3},{3,2,1}};
double a2[2][3] = {{4,5,6},{6,5,4}};

int numIn=2;
mpsArray** inVal = new mpsArray* [numIn];

inVal[0] = mpsCreateDoubleMatrix(2,3,mpsREAL);
inVal[1] = mpsCreateDoubleMatrix(2,3,mpsREAL);

double* data1 = (double *)( mpsGetData(inVal[0]) );
double* data2 = (double *)( mpsGetData(inVal[1]) );

for(int i=0; i<2; i++)
{
  for(int j=0; j<3; j++)
  {
    mpsIndex subs[] = { i, j };
    mpsIndex id = mpsCalcSingleSubscript(inVal[0], 2, subs);
    data1[id] = a1[i][j];
    data2[id] = a2[i][j];
  }
}

Create the MATLAB data to hold the output.

int numOut = 1;
mpsArray **outVal = new mpsArray* [numOut];

Call the deployed MATLAB function.
Specify the following as arguments:
- client context
- URL of the function
- Number of expected outputs
- Pointer to the mpsArray holding the outputs
- Number of inputs
- Pointer to the mpsArray holding the inputs
```
mpsStatus status = mpsruntime->feval(context,
    "http://localhost:9910/addmatrix/addmatrix",
    numOut, outVal, numIn, (const mpsArray**)inVal);
```
For more information about the feval function, see the reference material included in the $MPS_INSTALL/client folder, where $MPS_INSTALL is the name of your MATLAB Production Server installation folder.
Verify that the function call was successful using an if statement.
```
if (status==MPS_OK)
{
}
```

Inside the if statement, add code to process the output.

double* out = mpsGetPr(outVal[0]);

for (int i=0; i<2; i++)
{
  for (int j=0; j<3; j++)
  {        
    mpsIndex subs[] = {i, j};
    mpsIndex id = mpsCalcSingleSubscript(outVal[0], 2, subs);
    std::cout << out[id] << "\t";
  }
  std::cout << std::endl;
}

Add an else clause to the if statement to process any errors.

else  
{
  mpsErrorInfo error;
  mpsruntime->getLastErrorInfo(context, &error);
  std::cout << "Error: " << error.message << std::endl;
  switch(error.type)
  {
    case MPS_HTTP_ERROR_INFO:
      std::cout << "HTTP: " << error.details.http.responseCode << ": " 
          << error.details.http.responseMessage << std::endl;
    case MPS_MATLAB_ERROR_INFO:
      std::cout << "MATLAB: " << error.details.matlab.identifier 
          << std::endl;
      std::cout << error.details.matlab.message << std::endl;
    case MPS_GENERIC_ERROR_INFO:
      std::cout << "Generic: " << error.details.general.genericErrorMsg 
          << std::endl;
  }

  mpsruntime->destroyLastErrorInfo(&error);
}

Free the memory used by the inputs.

for (int i=0; i<numIn; i++)
  mpsDestroyArray(inVal[i]);
delete[] inVal;

Free the memory used by the outputs.

for (int i=0; i<numOut; i++)
  mpsDestroyArray(outVal[i]);
delete[] outVal;

Free the memory used by the client runtime.

mpsruntime->destroyConfig(config);
mpsruntime->destroyContext(context);
mpsTerminate();

Save the file.

The completed program should resemble the following:

#include <iostream>
#include <mps/client.h>

int main ( void )
{
  mpsClientRuntime* mpsruntime = mpsInitializeEx(MPS_CLIENT_1_1);

  mpsClientConfig* config;
  mpsStatus status = mpsruntime->createConfig(&config);

  mpsClientContext* context;
  status = mpsruntime->createContext(&context, config);

  double a1[2][3] = {{1,2,3},{3,2,1}};
  double a2[2][3] = {{4,5,6},{6,5,4}};

  int numIn=2;
  mpsArray** inVal = new mpsArray* [numIn];
  inVal[0] = mpsCreateDoubleMatrix(2,3,mpsREAL);
  inVal[1] = mpsCreateDoubleMatrix(2,3,mpsREAL);
  double* data1 = (double *)( mpsGetData(inVal[0]) );
  double* data2 = (double *)( mpsGetData(inVal[1]) );
  for(int i=0; i<2; i++)
  {
    for(int j=0; j<3; j++)
    {
      mpsIndex subs[] = { i, j };
      mpsIndex id = mpsCalcSingleSubscript(inVal[0], 2, subs);
      data1[id] = a1[i][j];
      data2[id] = a2[i][j];
    }
  }

  int numOut = 1;
  mpsArray **outVal = new mpsArray* [numOut];

  status = mpsruntime->feval(context,
               "http://localhost:9910/addmatrix/addmatrix",
               numOut, outVal, numIn, (const mpsArray **)inVal);

  if (status==MPS_OK)
  {
    double* out = mpsGetPr(outVal[0]);

    for (int i=0; i<2; i++)
    {
      for (int j=0; j<3; j++)
      {
        mpsIndex subs[] = {i, j};
        mpsIndex id = mpsCalcSingleSubscript(outVal[0], 2, subs);
        std::cout << out[id] << "\t";
      }
      std::cout << std::endl;
    }
  }
  else
  {
    mpsErrorInfo error;
    mpsruntime->getLastErrorInfo(context, &error);
    std::cout << "Error: " << error.message << std::endl;

    switch(error.type)
    {
    case MPS_HTTP_ERROR_INFO:
      std::cout << "HTTP: " 
          << error.details.http.responseCode 
          << ": " << error.details.http.responseMessage
          << std::endl;
    case MPS_MATLAB_ERROR_INFO:
      std::cout << "MATLAB: " << error.details.matlab.identifier 
          << std::endl;
      std::cout << error.details.matlab.message << std::endl;
    case MPS_GENERIC_ERROR_INFO:
      std::cout << "Generic: " 
          << error.details.general.genericErrorMsg 
          << std::endl;
    }
    mpsruntime->destroyLastErrorInfo(&error);
  }

  for (int i=0; i<numIn; i++)
    mpsDestroyArray(inVal[i]);
  delete[] inVal;

  for (int i=0; i<numOut; i++)
    mpsDestroyArray(outVal[i]);
  delete[] outVal;

  mpsruntime->destroyConfig(config);
  mpsruntime->destroyContext(context);
  mpsTerminate();
}

Compile the application.

To compile your client code, the compiler needs access to client.h. This header file is stored in $MPSROOT/client/c/include/mps/.

To link your application, the linker needs access to the following files stored in $MPSROOT/client/c/matlabroot/toolbox/compiler_sdk/mps_client/c/:

Files Required for Linking

Windows^®	UNIX^®/Linux	Mac OS X
`$arch\lib\mpsclient.lib`	`$arch/lib/libprotobuf.so`	`$arch/lib/libprotobuf.dylib`
	`$arch/lib/libcurl.so`	`$arch/lib/libcurl.dylib`
	`$arch/lib/libmwmpsclient.so`	`$arch/lib/libmwmpsclient.dylib`
	`$arch/lib/libmwcpp11compat.so`

Run the application.

To run your application, add the following files stored in $MPSROOT/client/c/matlabroot/toolbox/compiler_sdk/mps_client/c/ to the application's path:

Files Required for Running

Windows	UNIX/Linux	Mac OS X
`$arch\lib\mpsclient.dll`	`$arch/lib/libprotobuf.so`	`$arch/lib/libprotobuf.dylib`
`$arch\lib\libprotobuf.dll`	`$arch/lib/libcurl.so`	`$arch/lib/libcurl.dylib`
`$arch\lib\libcurl.dll`	`$arch/lib/libmwmpsclient.so`	`$arch/lib/libmwmpsclient.dylib`
	`$arch/lib/libmwcpp11compat.so`

The client invokes addmatrix function on the server instance and returns the following matrix at the console:

5.0 7.0 9.0
9.0 7.0 5.0

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