Readers Writers with Processes and Threads
Write two programs implementing ``reader pritority readers-writers synchronization'''' on files. One program will use processes, created with fork(), and synchronized with semaphores. The other program will use threads, created with pthread_create(), and synchronized with mutexes and conditions. In the following, the word "process" is used to describe either a process or thread, as appropriate.
Your program will create two readers and two writers. All four will access a common file, named ``SharedFile.'''' This file should contain a single number. The file should be created and given an initial value of 0 before the processes/threads are spawned.
The reader pseudocode:
repeat 20 times:
acquire read lock
read the number from SharedFile
release the read lock
print a message identifying the process, and the value read from SharedFile
sleep for a random period between 100 and 200 msec
The writer pseudocode:
repeat 20 times:
acquire write lock
read the number from SharedFile
increment it by a random value between 1 and 6
write the new value to SharedFile
release the write lock
print a message identifying the process, and the value written to SharedFile
sleep for a random period between 100 and 400 msec
Submit ONLY your C/C++ source code. Be sure to put your name and course in the comment header. The code must run on the "algebra and friends" machines. Use good programming style (comments, indentation, meaningful identifiers, etc.)