undefined reference to `strlwr' [closed]

Answer 1

strlwr() is not standard C function. Probably it's provided by one implementation while the other compiler you use don't.

You can easily implement it yourself:

#include <string.h>
#include<ctype.h>

char *strlwr(char *str)
{
  unsigned char *p = (unsigned char *)str;

  while (*p) {
     *p = tolower((unsigned char)*p);
      p++;
  }

  return str;
}