From 375c72f0534f5cb27100225780744d96ba543140 Mon Sep 17 00:00:00 2001
From: Brandon Rodriguez <brodriguez8774@gmail.com>
Date: Thu, 16 Apr 2020 23:59:00 -0400
Subject: [PATCH] Implement initial threading logic
---
documents/references.md | 11 ++++++++++
main.c | 48 ++++++++++++++++++++++++++++++++++++++++-
makefile | 2 +-
readme.md | 2 +-
4 files changed, 60 insertions(+), 3 deletions(-)
diff --git a/documents/references.md b/documents/references.md
index 8b05480..71982ef 100755
--- a/documents/references.md
+++ b/documents/references.md
@@ -7,6 +7,17 @@ Includes anything from stack overflow links to notes about logic from previous w
## References
+### Pthreads Reference
+<https://www.cs.cmu.edu/afs/cs/academic/class/15492-f07/www/pthreads.html>
+<https://www.geeksforgeeks.org/thread-functions-in-c-c/>
+
+### C Sleep
+<https://stackoverflow.com/a/10923084>
+
+### Copy Variable to New Memory Location
+This helps ensure variable values passed to threads are thread-safe and not shared.
+<https://stackoverflow.com/a/25489311>
+
### Makefile
* Purpose of ".PHONY" - <https://stackoverflow.com/a/2145605>
* Have one command execute another - <https://stackoverflow.com/a/48552668>
diff --git a/main.c b/main.c
index a2dfc2e..4b94e33 100755
--- a/main.c
+++ b/main.c
@@ -1,13 +1,15 @@
/**
- *
+ * Uses pthreads to implement the "Dining Philosophers" problem.
*/
// Import headers.
+#include <pthread.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#include <unistd.h>
// Constant Defines.
@@ -17,6 +19,7 @@
// Method Declaration.
+void* start_thread();
/**
@@ -26,5 +29,48 @@
int main(int argc, char* argv[]) {
printf("Starting program.\n");
+ // Create variables.
+ pthread_t* thread_array = calloc(10, sizeof(pthread_t));
+ int* thread_results = calloc(10, sizeof(int));
+ int index = 0;
+
+ // Create threads.
+ while (index < 10) {
+ // Create new "thread_number" int from index and save to new memory location. Then create thread.
+ int* thread_number = calloc(1, sizeof(int));
+ *thread_number = index + 1;
+ pthread_create(&thread_array[index], NULL, start_thread, (void*) thread_number);
+ index += 1;
+ }
+
+ // Join threads and handle results.
+ index = 0;
+ while (index < 10) {
+ // Get and save return value. Free original pointer for int that was passed into threads.
+ void* ret_val = NULL;
+ pthread_join(thread_array[index], &ret_val);
+ thread_results[index] = *(int*) ret_val;
+ free(ret_val);
+ printf("Got thread #%d results.\n", thread_results[index]);
+ index += 1;
+ }
+
+ // Free variables.
+ free(thread_array);
+ free(thread_results);
+
printf("\n\nTerminating program.\n");
}
+
+
+/**
+ * Function threads call on start.
+ */
+void* start_thread(void* thread_num) {
+ printf("Started thread #%d.\n", *(int*)thread_num);
+
+ sleep(1);
+
+ printf("Exiting thread #%d.\n", *(int*)thread_num);
+ pthread_exit(thread_num);
+}
diff --git a/makefile b/makefile
index 9180187..4837313 100755
--- a/makefile
+++ b/makefile
@@ -11,7 +11,7 @@ all: compile run clean
# Compile program.
compile:
- gcc -Wall -Wpedantic -std=c99 *.c
+ gcc -Wall -Wpedantic -std=c99 *.c -lpthread
# Compile and run program.
diff --git a/readme.md b/readme.md
index a9fb3bf..fef1a98 100755
--- a/readme.md
+++ b/readme.md
@@ -2,7 +2,7 @@
## Description
-A program using pthreads to do the "Dining Philosophers" problem.
+A program using pthreads to implement the "Dining Philosophers" problem.
## Running Program
--
GitLab