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This example shows how to generate C/C++ libraries or executables that detect and report run-time errors such as out-of-bounds array indexing. If the generated code detects an error, it reports a message and terminates the program. You can detect and fix errors that occur only on the target hardware.

Write the function getelement that indexes into one structure field using the value of the other structure field.

function y = getelement(S)
y = S.A(S.u);
end

Create a code configuration object for a standalone library or executable. For example, create a code configuration object for a static library. Enable the code generation report.

cfg = coder.config('lib');
cfg.GenerateReport = true;

Enable generation of run-time error detection and reporting.

cfg.RuntimeChecks = true;

Define an example input that you can use to specify the properties of the input argument.

S.A = ones(2,2);
S.u = 0;

Generate code.

codegen -config cfg getelement -args {S}

To open the code generation report, click the View report link.

When the report opens, you see the generated C code. You can see the code that checks for an error and calls a function to report the error. For example, if the code detects an out-of-bounds array indexing error, it calls rtDynamicBoundsError to report the error and terminate the program.

/* Include Files */
#include "rt_nonfinite.h"
#include "getelement.h"
#include "getelement_rtwutil.h"
#include <stdio.h>
#include <stdlib.h>

/* Variable Definitions */
static rtBoundsCheckInfo emlrtBCI = { 1, 4, 2, 5, "S.A", "getelement",
  "C:\\coder\\runtime checks\\getelement.m", 0 };

static rtDoubleCheckInfo emlrtDCI = { 2, 5, "getelement",
  "C:\\coder\\runtime checks\\getelement.m", 1 };

/* Function Definitions */

/*
 * Arguments    : const struct0_T *S
 * Return Type  : double
 */
double getelement(const struct0_T *S)
{
  double d0;
  int i0;
  d0 = S->u;
  if (d0 != (int)floor(d0)) {
    rtIntegerError(d0, &emlrtDCI);
  }

  i0 = (int)d0;
  if (!((i0 >= 1) && (i0 <= 4))) {
    rtDynamicBoundsError(i0, 1, 4, &emlrtBCI);
  }

  return S->A[i0 - 1];
}

The error reporting software uses fprintf to write error messages to stderr. It uses abort to terminate the application. If fprintf and abort are not available, you must provide them. The abort function abruptly terminates the program. If your system supports signals, you can catch the abort signal (SIGABRT) so that you can control the program termination.