Chapter 4

chp4/writev.c

@@ -0,0 +1,45 @@
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/uio.h>
+#include <unistd.h>
+
+int main(void) {
+    struct iovec iov[3];
+
+    char *buf[] = {
+        "The term buccaneer comes from the word boucan.\n",
+        "A boucan is a wooden frame used for cooking meet.\n",
+        "Buccaneer is the West Indies name for a pirate.\n"
+    };
+
+    int fd = open("buccaneer.txt", O_WRONLY | O_CREAT | O_TRUNC);
+    if (fd == -1) {
+        perror("open");
+        return 1;
+    }
+
+    // fill out three iovec structures
+    for (int i = 0; i < 3; i++) {
+        iov[i].iov_base = buf[i];
+        iov[i].iov_len = strlen(buf[i]) + 1;
+    }
+
+    // with a single call, write them all out
+    ssize_t nr = writev(fd, iov, 3);
+    if (nr == -1) {
+        perror("writev");
+        return 1;
+    }
+
+    printf("wrote %lu bytes\n", nr);
+
+    if (close(fd)) {
+        perror("close");
+        return 1;
+    }
+
+    return 0;
+}