--- a/th_ioctx.h	Fri Apr 07 02:49:08 2017 +0300
+++ b/th_ioctx.h	Wed May 10 21:00:37 2017 +0300
@@ -23,26 +23,28 @@
 struct th_ioctx_ops;
 
 
+/** I/O context structure
+ */
 typedef struct th_ioctx
 {
-    char *filename;
-    char *mode;
-    void *data;
-    time_t atime;
-    int64_t size;
-    int status;
-    size_t line;
+    char *filename;     ///< Context filename, if any. May be NULL.
+    char *mode;         ///< Context's stdio open "mode", may also be NULL.
+    void *data;         ///< Internal data
+    time_t atime;       ///< Last access time
+    int64_t size;       ///< Size in bytes
+    int status;         ///< Status
+    size_t line;        ///< Line number
 
     void (*error)(struct th_ioctx *, const int err, const char *msg);
     void (*msg)(struct th_ioctx *, const int level, const char *msg);
 
-    const struct th_ioctx_ops *fops;
+    const struct th_ioctx_ops *fops; ///< Pointer to I/O ops struct to be used with this context
 } th_ioctx;
 
 
 typedef struct th_ioctx_ops
 {
-    char    *name;
+    char    *name;                   ///< Name of this I/O ops definition
 
     int     (*fopen)(th_ioctx *ctx);
     void    (*fclose)(th_ioctx *ctx);