Add C programs from last 2 weeks

.gitignore

@@ -4,7 +4,10 @@
 *.exe
 ashwathama
 bash_gitignore.sh
+endian
 garibsh
 ior
+myps
 pid
 sync
+threads

endianness.c

@@ -0,0 +1,19 @@
+#include<stdio.h>
+#include<stdlib.h>
+
+int main(void) {
+
+  int num = 0x0A0B0C0D;
+  /*
+    0A 0B 0C 0D
+    high     low
+  */
+  unsigned char *ptr = (unsigned char*)&num;
+
+  if (*ptr == 0x0D) {
+    printf("Little endian\n");
+  } else {
+    printf("Big endian\n");
+  }
+  return 0;
+}

myps.c

@@ -0,0 +1,65 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/sysctl.h>
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/user.h>
+#include <string.h>
+#include <errno.h>
+
+int main(void) {
+    int mib[3];
+    struct kinfo_proc *procs = NULL;
+    size_t size = 0;
+
+    // MIB array: [CTL_KERN, KERN_PROC, KERN_PROC_ALL]
+    // This will query all running processes.
+    mib[0] = CTL_KERN;
+    mib[1] = KERN_PROC;
+    mib[2] = KERN_PROC_ALL;
+
+    // First call with a NULL buffer to get the size needed.
+    if (sysctl(mib, 3, NULL, &size, NULL, 0) == -1) {
+        fprintf(stderr, "sysctl (get size) failed: %s\n", strerror(errno));
+        return 1;
+    }
+
+    // Allocate a buffer large enough to hold the process list.
+    procs = (struct kinfo_proc *)malloc(size);
+    if (!procs) {
+        fprintf(stderr, "malloc failed\n");
+        return 1;
+    }
+
+    // Second call gets the actual process data.
+    if (sysctl(mib, 3, procs, &size, NULL, 0) == -1) {
+        fprintf(stderr, "sysctl (get data) failed: %s\n", strerror(errno));
+        free(procs);
+        return 1;
+    }
+
+    // Number of processes returned
+    int count = (int)(size / sizeof(struct kinfo_proc));
+
+    // Print a simple header
+    printf("%5s  %-16s  %5s\n", "PID", "COMMAND", "STATE");
+    printf("------------------------------------------------\n");
+
+    for (int i = 0; i < count; i++) {
+        // Extract PID and command name
+        pid_t pid = procs[i].kp_proc.p_pid;
+        char  comm[MAXCOMLEN+1];
+        strncpy(comm, procs[i].kp_proc.p_comm, MAXCOMLEN);
+        comm[MAXCOMLEN] = '\0';
+
+        // The process state is in p_stat (numeric on macOS).
+        // Some typical BSD states (historical):
+        //  1=SIDL (startup), 2=SRUN (running), 3=SSLEEP, 4=SSTOP, 5=SZOMB, etc.
+        int state = procs[i].kp_proc.p_stat;
+
+        printf("%5d  %-16s  %5d\n", pid, comm, state);
+    }
+
+    free(procs);
+    return 0;
+}

symlink_to_pid.c

@@ -0,0 +1 @@
+pid.c

threads.c

@@ -0,0 +1,47 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include <signal.h>
+#include <unistd.h>
+
+volatile sig_atomic_t stop_thread = 0;
+
+void handle_signal(int signal) {
+    stop_thread = 1;
+}
+
+void* increment_counter(void* arg) {
+    int* counter = (int*)arg;
+    while (!stop_thread) {
+        (*counter)++;
+        printf("Counter: %d\n", *counter);
+        sleep(1); // Sleep for 1 second
+    }
+    return NULL;
+}
+
+int main() {
+    int counter = 0;
+    pthread_t thread_id;
+
+    signal(SIGINT, handle_signal);
+
+    if (pthread_create(&thread_id, NULL, increment_counter, &counter) != 0) {
+        fprintf(stderr, "Error creating thread\n");
+        return 1;
+    }
+
+    for (int i = 0; i < 10; i++) {
+        if (stop_thread) {
+            break; // Exit if signal received
+        }
+        sleep(1);
+    }
+
+    stop_thread = 1;
+
+    pthread_join(thread_id, NULL);
+
+    printf("Final Counter Value: %d\n", counter);
+    return 0;
+}