Write a program, analogous to the Unix/Linux cat command, that uses mmap() and write) system calls (instead of read) or write)) to copy a source file to the screen. Use fstat() to obtain the size of the input file which can be used to size the required memory mapping. The statement to write the file contents to STDOUT is write (STDOUT_FILENO, addr, sb.st_size): where addr is the start of the mapping, gotten from mmap() and, sb. st_size is the size of the mapping returned by fstat() in the sb_struct. Write a program to create a mmap() that is shared by multiple threads. Use fstat() to obtain the size of the mapped file to size the mapping. Find out the number of logical processors (or cores) available programmatically by calling sysconf(), as shown, and display this number. int numCPU = sysconf(_SC_NPROCESSORS_ONLN): For this exercise, however, you are going to create four (4) threads only. Every thread should see the mapping. Each thread will display separate partial contents (sb.st_size/4 bytes) of the file. Finally, unmap and close the file