port from argv

~/C/libserialport/listen.c

@@ -1,50 +1,67 @@
 #include <libserialport.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
+#include <stdbool.h>
 
 /* Helper function for error handling. */
 int check(enum sp_return result);
 
 int main(int argc, char **argv) {
-  int result;
-  const int size = 30;
-  char *buffer = malloc(size + 1);
-  const char *port_name = "/dev/ttyACM0";
-  const unsigned int timeout = 1000;
   struct sp_port *serial_port;
+  char *port_name = "/dev/ttyACM0";
 
+  const int size = 256;
+  char *buffer = malloc(size + 1);
+
+  const unsigned int timeout = 1000;
+  int result;
+
+  if (argc != 2) {
+    printf("Usage: %s <port>\n", argv[0]);
+    return -1;
+  } else {
+    port_name = argv[1];
+  }
+
+  printf("Connecting to '%s'...\n", port_name);
   check(sp_get_port_by_name(port_name, &serial_port));
-
-  printf("Opening port.\n");
   check(sp_open(serial_port, SP_MODE_READ_WRITE));
 
-  printf("Setting port to 9600 8N1, no flow control.\n");
   check(sp_set_baudrate(serial_port, 9600));
   check(sp_set_bits(serial_port, 8));
   check(sp_set_parity(serial_port, SP_PARITY_NONE));
   check(sp_set_stopbits(serial_port, 1));
   check(sp_set_flowcontrol(serial_port, SP_FLOWCONTROL_NONE));
+  puts("Connected.\n");
 
-  result =
-      check(sp_blocking_write(serial_port, "ping", strlen("ping"), timeout));
 
-  while (1) {
-    result = check(sp_blocking_read(serial_port, buffer, size, timeout));
+  while (true) {
+    int pos = 0;
 
-    if (result == -1) {
-      printf("Error reading from serial port\n");
-      break;
-    } else if (result == 0) {
-      printf("No more data\n");
-      break;
-    } else {
-      buffer[result] = '\0';
-      printf("=====\n%s\n", buffer);
+    while (pos < size) {
+      result = check(sp_blocking_read(serial_port, buffer + pos, 1, timeout));
+
+      if (result == -1) {
+        printf("Error reading from serial port\n");
+        break;
+      } else if (result == 0) {
+        printf("No more data\n");
+        break;
+      } else {
+        if (buffer[pos] == '\n') {
+          buffer[pos] = '\0';
+          break;
+        } else
+          pos++;
+      }
+
+      puts(buffer);
     }
   }
 
   free(buffer);
+
+  return 0;
 }
 
 /* Helper function for error handling. */