Make filenames from dir name

diff --git a/batteryviewer.c b/batteryviewer.c
index 540db8e7c21c024ab0dabde05d6e5236eaa16c20..9f1dedd8791a94630a302a9d15e9b34c011b6c3c 100644 (file)
--- a/batteryviewer.c
+++ b/batteryviewer.c
@@ -1,11 +1,27 @@
+// For vasprintf
+#define _GNU_SOURCE
+
 #include "chart.h"
 #include <ctype.h>
 #include <errno.h>
 #include <gtk/gtk.h>
 #include <math.h>
+#include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 
+char *sasprintf(const char *fmt, ...) {
+  char *result;
+  va_list args;
+  va_start(args, fmt);
+  if (vasprintf(&result, fmt, args) == -1) {
+    fprintf(stderr, "Can't allocate memory!?\n");
+    abort();
+  }
+  va_end(args);
+  return result;
+}
+
 struct State {
   char *voltage_filename;
   char *current_filename;
@@ -79,9 +95,10 @@ static void activate(GtkApplication *app, gpointer user_data) {
 }
 
 int main(int argc, char **argv) {
+  char *battery_dir = "/sys/class/power_supply/BAT0";
   struct State state = {
-      .voltage_filename = "/sys/class/power_supply/BAT0/voltage_now",
-      .current_filename = "/sys/class/power_supply/BAT0/current_now",
+      .voltage_filename = sasprintf("%s/voltage_now", battery_dir),
+      .current_filename = sasprintf("%s/current_now", battery_dir),
   };
 
   GtkApplication *app = gtk_application_new("com.scottworley.batteryviewer",