fixed the gpio code
diff --git a/bbb_cape/src/bbb/gpios.cc b/bbb_cape/src/bbb/gpios.cc
index 8594ba4..79d38bc 100644
--- a/bbb_cape/src/bbb/gpios.cc
+++ b/bbb_cape/src/bbb/gpios.cc
@@ -2,67 +2,72 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <errno.h>
+#include <string.h>
 
 #include "aos/common/logging/logging_impl.h"
 
 namespace bbb {
 
-Pin::Pin() {}
-
-Pin::~Pin() {
-  // Unexport the pin.
-  if ((handle_ = fopen("/sys/class/gpio/unexport", "ab")) == NULL) {
-    LOG(WARNING, "Could not open file to unexport pin.\n");
-    // There's nothing intelligent we can really do here.
-    return;
-  }
-
-  fprintf(handle_, "%d", kernel_pin_);
-  fclose(handle_);
-}
-
-bool Pin::InitPin(int bank, int pin) {
-  kernel_pin_ = bank * 32 + pin;
-
+GpioPin::GpioPin(int bank, int pin, bool input, bool initial_value)
+    : bank_(bank), pin_(pin), kernel_pin_(bank * 32 + pin) {
   // Export the pin.
-  if ((handle_ = fopen("/sys/class/gpio/export", "ab")) == NULL) {
-    LOG(ERROR, "Could not open file for exporting pin.\n");
-    return false;
+  FILE *export_handle = fopen("/sys/class/gpio/export", "a");
+  if (export_handle == NULL) {
+    LOG(WARNING,
+        "Could not open file to export pin (%d,%d) because of %d: %s.\n",
+        bank_, pin_, errno, strerror(errno));
+  } else {
+    if (fprintf(export_handle, "%d", kernel_pin_) < 0) {
+      LOG(WARNING, "Could not write to file %p to export pin (%d,%d) because "
+                   "of %d: %s.\n",
+          export_handle, bank_, pin_, errno, strerror(errno));
+    }
+    if (fclose(export_handle) == -1) {
+      LOG(WARNING, "fclose(%p) failed with %d: %s\n", export_handle, errno,
+          strerror(errno));
+    }
   }
 
-  fprintf(handle_, "%d", kernel_pin_);
-  fclose(handle_);
-  return true;
+  char direction_path[64];
+  snprintf(direction_path, sizeof(direction_path),
+           "/sys/class/gpio/gpio%d/direction", kernel_pin_);
+
+  FILE *direction_handle = fopen(direction_path, "w");
+  if (direction_handle == NULL) {
+    LOG(FATAL, "fopen(%s, \"w+\") failed with %d: %s\n",
+        direction_path, errno, strerror(errno));
+  }
+
+  if (fputs(input ? "in" : (initial_value ? "high" : "low"),
+            direction_handle) < 0) {
+    LOG(FATAL, "setting direction for pin (%d,%d) failed with %d: %s\n",
+        bank_, pin_, errno, strerror(errno));
+  }
+  if (fclose(direction_handle) == -1) {
+    LOG(WARNING, "fclose(%p) failed with %d: %s\n", direction_handle, errno,
+        strerror(errno));
+  }
 }
 
-bool Pin::DoPinDirSet(int direction) {
-  char type_path[64];
-  snprintf(type_path, sizeof(type_path), "/sys/class/gpio/gpio%d/direction",
-           kernel_pin_);
-
-  if ((handle_ = fopen(type_path, "rb+")) == NULL) {
-    LOG(ERROR, "Unable open file for pin direction setting.\n");
-    return false;
+GpioPin::~GpioPin() {
+  // Unexport the pin.
+  FILE *unexport_handle = fopen("/sys/class/gpio/unexport", "a");
+  if (unexport_handle == NULL) {
+    LOG(WARNING,
+        "Could not open file to unexport pin (%d,%d) because of %d: %s.\n",
+        bank_, pin_, errno, strerror(errno));
+  } else {
+    if (fprintf(unexport_handle, "%d", kernel_pin_) < 0) {
+      LOG(WARNING, "Could not write to file %p to unexport pin (%d,%d) because "
+                   "of %d: %s.\n",
+          unexport_handle, bank_, pin_, errno, strerror(errno));
+    }
+    if (fclose(unexport_handle) == -1) {
+      LOG(WARNING, "fclose(%p) failed with %d: %s\n", unexport_handle, errno,
+          strerror(errno));
+    }
   }
-
-  switch (direction) {
-    case 1:
-      // Input.
-      fprintf(handle_, "in");
-      break;
-    case 2:
-      // Output.
-      // If it's an output, we should specify an initial direction.
-      fprintf(handle_, "low");
-      break;
-    default:
-      LOG(ERROR, "Invalid direction identifier %d.\n", direction);
-      fclose(handle_);
-      return false;
-  }
-
-  fclose(handle_);
-  return true;
 }
 
 }  // namespace bbb