MATLAB Compiler

Controlling #line Directives in Output Code

#line preprocessing directives inform a C/C++ compiler that the C/C++ code was generated by another tool (MATLAB Compiler) and they identify the correspondence between the generated code and the original source code (M-file). You can use the #line directives to help debug your M-file(s). Most C language debuggers can display your M-file source code. These debuggers allow you to set breakpoints, single step, and so on at the M-file code level when you use the #line directives.

Use the line:setting option to include #line preprocessor directives in your generated C or C++ output. The possible values for setting are

• on
• off

Not specifying any line setting uses the default of off, which does not include any #line preprocessor directives in the generated C/C++ source.

Note    When using the #line directive, the page-width directive is disabled in order to make the code work properly with the C debugger.

Include #line Directives

To include #line directives in your generated C or C++ code, use

• mcc -A line:on ...
  

The Hello, World example produces the following code segment when this option is selected. (Note that several lines have been truncated for readability.)

• #line 1 "D:\\work\\hello.m"                                   /* Line 1 */
  static void Mhello(void) {
      #line 1 "D:\\work\\hello.m"                               /* Line 1 */
      mclMlineEnterFunction("D:\\work\\hello.m", "hello")
      #line 1 "D:\\work\\hello.m"                               /* Line 1 */
      mexLocalFunctionTable save_local_function_table_ = -->
      #line 1 "D:\\work\\hello.m"                               /* Line 1 */
      mxArray * ans = NULL;
      /*
       * % This is the hello, world function written in M code
       * fprintf(1,'Hello, World\n' );
       */
      #line 3 "D:\\work\\hello.m"                               /* Line 3 */
      mclMline(3);
      #line 3 "D:\\work\\hello.m"                               /* Line 3 */
      mclAssignAns(&ans, mlfNFprintf(0, mlfScalar(1), mxCreateString("Hello,-->
      #line 3 "D:\\work\\hello.m"                               /* Line 3 */
      mxDestroyArray(ans);
      #line 3 "D:\\work\\hello.m"                               /* Line 3 */
      mclSetCurrentLocalFunctionTable(save_local_function_table_);
      #line 3 "D:\\work\\hello.m"                               /* Line 3 */
      mclMlineExitFunction();
      #line 3 "D:\\work\\hello.m"                               /* Line 3 */
  }
  

In this example, Line 1 points to lines in the generated C code that were produced by line 1 from the M-file, that is

• function hello
  

Line 3 points to lines in the C code that were produced by line 3 of the M-file, or

• fprintf(1,'Hello, World\n' );
  

Controlling Comments in Output Code

Controlling Information in Run-Time Errors