mexErrMsgIdAndTxt (C and Fortran)

Display error message with identifier and return to MATLAB prompt

C Syntax

#include "mex.h"
void mexErrMsgIdAndTxt(const char *errorid, 
  const char *errormsg, ...);

Fortran Syntax

#include "fintrf.h"
subroutine mexErrMsgIdAndTxt(errorid, errormsg)
character*(*) errorid, errormsg

Arguments

errorid

String containing a MATLAB^® message identifier. For information on creating identifiers, see MException.

errormsg

String to display, specified as const char* in C or character*(*) in Fortran. In C, the function supports either UTF-8 or local code page (LCP) encoding and the string can include conversion specifications, used by the ANSI^® C printf function. The encoding for both the message text and the conversion arguments must be the same.

...

In C, any arguments used in the message. Each argument must have a corresponding conversion specification. Refer to your C documentation for printf conversion tables.

Description

The mexErrMsgIdAndTxt function writes an error message to the MATLAB window. For more information, see the error function syntax statement using a message identifier. After the error message prints, MATLAB terminates the MEX file and returns control to the MATLAB prompt.

Calling mexErrMsgIdAndTxt does not clear the MEX file from memory. So, mexErrMsgIdAndTxt does not invoke the function registered through mexAtExit.

If your application called mxCalloc or one of the mxCreate* routines to allocate memory, mexErrMsgIdAndTxt automatically frees the allocated memory.

Note

If you get warnings when using mexErrMsgIdAndTxt, you might have a memory management compatibility problem. For more information, see Memory Management Issues.

Remarks

In addition to the errorid and errormsg, the mexErrMsgIdAndTxt function determines where the error occurred, and displays the following information. For example, in the function foo, mexErrMsgIdAndTxt displays:

Error using foo

If you compile your MEX file with the MinGW-w64 compiler, see the limitations with exception handling topic in Troubleshooting and Limitations Compiling C/C++ MEX Files with MinGW-w64.

Examples

See these examples in matlabroot/extern/examples/refbook:

• arrayFillGetPr.c

• matrixDivide.c

• timestwo.F

• xtimesy.F

Validate char Input

The following code snippet checks if input argument, prhs[0], is a string. If not, the code displays a warning. If there is an error reading the input string, the code displays an error message and terminates the MEX file.

char *buf;
int buflen;

// initialize variables

if (mxIsChar(prhs[0])) {
    if (mxGetString(prhs[0], buf, buflen) == 0) {
        mexPrintf("The input string is:  %s\n", buf);
    }
    else { 
        mexErrMsgIdAndTxt("MyProg:ConvertString",
           "Could not convert string data.");
        // exit MEX file
    } 
}
else {
    mexWarnMsgIdAndTxt("MyProg:InputString",
        "Input should be a string to print properly.");
}

// continue with processing

Version History

Introduced before R2006a

R2020b: UTF-8 support added

The mexErrMsgIdAndTxt function accepts UTF-8 encoded data in addition to supporting LCP encoded strings for backward compatibility.