Question

To produce millisecond using clock function after strcat but it simply crash, what could be the problem?

FREObject result = 0;

uint32_t len = -1;
const uint8_t *str = 0;
char *temp = "Millisecond: ";
uint8_t *strAll;

clock_t curtime = clock();

double *asc = (double *) curtime;  //Using double datatype?

if(FREGetObjectAsUTF8(argv[0], &len, &str) == FRE_OK) {

  strAll = (char *)malloc(strlen(temp) + strlen(str) + 1 + strlen(asc) + 1);
  strcpy(strAll,temp);
  strcat(strAll,str);
  strcat(strAll," ");
  strcat(strAll,(char *)asc);  //Is this correct?
}

FRENewObjectFromUTF8(strlen((const char *)strAll)+1, (const uint8_t *)strAll, &result);         

return result;

Answer 1

The assignment to asc is extremely dubious:

double *asc = (double *) curtime;  //Using double datatype?

You can measure the difference between two clock() values, to determine the processor time used.

You might get more nearly successful results with:

double asc = curtime;

The strlen() operation is undefined – under either definition of asc:

strAll = (char *)malloc(strlen(temp) + strlen(str) + 1 + strlen(asc) + 1);

Then the strcat() operation is going fail horribly; you have to convert the double to a string before you can concatenate the string to another.

strcat(strAll,(char *)asc);  //Is this correct?

So, you have a lot of work to do. You need to decide whether clock() is the right system call. If it is, you have to fix the sizing and the conversion of asc or curtime to a string before you concatenate it to the result.