Add C src for ShmCreate.dylib

src/main/c/ShmCreate.c

@@ -0,0 +1,67 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+// Function to get the size of a shared memory segment given its file descriptor
+long get_shared_memory_size(int fd) {
+    struct stat shm_stat;
+    if (fstat(fd, &shm_stat) == -1) {
+        perror("fstat");
+        return -1;
+    }
+    return (long)shm_stat.st_size;
+}
+
+// Function to create a shared memory segment, modified to accept a long for size
+int create_shared_memory(const char *name, long size) {
+    int fd = shm_open(name, O_CREAT | O_RDWR, 0666);
+    if (fd < 0) {
+        perror("shm_open");
+        return -1;
+    }
+    long already_size = get_shared_memory_size(fd);
+    if (already_size > 0) {
+        return fd;
+    }
+
+    if (ftruncate(fd, size) == -1) {
+        perror("ftruncate");
+        close(fd);
+        return -1;
+    }
+
+    return fd;
+}
+
+// Function to unlink a shared memory segment
+void unlink_shared_memory(const char *name) {
+    if (shm_unlink(name) == -1) {
+        perror("shm_unlink");
+    }
+}
+
+int main() {
+    const char *shm_name = "/myshm";
+    size_t shm_size = 1024;
+
+    // Create shared memory
+    int shm_fd = create_shared_memory(shm_name, shm_size);
+    if (shm_fd < 0) {
+        exit(EXIT_FAILURE);
+    }
+
+    // Perform operations with shared memory here
+    // ...
+
+    // Close the shared memory file descriptor
+    close(shm_fd);
+
+    // Unlink shared memory
+    unlink_shared_memory(shm_name);
+
+    return 0;
+}
+