I can't figure out what to do to make this work. Here's my code:

char* testStr = "          trim this           ";
char** pTestStr = &testStr;
trim(pTestStr);

int trim(char** pStr)
{
 char* str = *pStr;
 while(isspace(*str)) {
  (*pStr)++;
  str++;
 }

 if(*str == 0) {
  return 0;
 }

 char *end = str + strlen(str) - 1;
 while(end > str && isspace(*end))
  end--;
 *(end+1) = 0;

 return 0;
}

I get an access violation on *(end+1) = 0;, but I can't declare my testStr[] as such to avoid that, because I can't pass the pointers that way. Any ideas?