Added comments.

FossilOrigin-Name: 74aa1d5b893fb4d2ba1fd030ea9616f37a3aefc8dab41ceaf99bf2712a46ffdd

src/capwap/cw_save_file.c

@@ -1,8 +1,39 @@
+/*
+    This file is part of libcapwap.
+
+    libcapwap is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    libcapwap is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with libcapwap.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+/**
+ *@file
+ */
+
 #include <stdio.h>
 
 #include "file.h"
 
-
+/**
+ * Save data from memory to a file
+ * @param filename file to save data to
+ * @data pointer to data to save
+ * @len number of bytes to save
+ * @return number of bytes saved
+ *
+ * Use ferror to determine if an error has occured, when 
+ * the return value (number of bytes written) differs from len.
+ */ 
 int cw_save_file(const char *filename, char *data, int len)
 {
 	FILE *outfile = fopen(filename, "wb");