Some versions of doxygen seem to object to "@ret None" or similar.

src/core/buffer.c

@@ -48,8 +48,8 @@
  * Initialise a buffer.
  *
  * @v buffer		The buffer to be initialised
- * @ret None
- * @err None
+ * @ret None		-
+ * @err None		-
  *
  * Set @c buffer->start and @c buffer->end before calling init_buffer().
  * init_buffer() will initialise the buffer to the state of being
@@ -72,8 +72,8 @@ void init_buffer ( struct buffer *buffer ) {
  * @v desc		A descriptor for the free block
  * @v block		Start address of the block
  * @v split		Address at which to split the block
- * @ret None
- * @err None
+ * @ret None		-
+ * @err None		-
  *
  * Split a free block into two separate free blocks.  If the split
  * point lies outside the block, no action is taken; this is not an
@@ -120,8 +120,8 @@ static void split_free_block ( struct buffer_free_block *desc,
  * @v buffer		The buffer containing the block
  * @v desc		A descriptor for the free block
  * @v prev_block	Address of the previous block
- * @ret None
- * @err None
+ * @ret None		-
+ * @err None		-
  *
  * Marks a free block as used, i.e. removes it from the free list.
  *

src/core/console.c

@@ -12,8 +12,8 @@ static struct console_driver console_drivers_end[0] __table_end ( console );
  * Write a single character to each console device.
  *
  * @v character		Character to be written
- * @ret None
- * @err None
+ * @ret None		-
+ * @err None		-
  *
  * The character is written out to all enabled console devices, using
  * each device's console_driver::putchar() method.
@@ -36,10 +36,10 @@ void putchar ( int character ) {
 /**
  * Check to see if any input is available on any console.
  *
- * @v None
+ * @v None		-
  * @ret console		Console device that has input available, if any.
  * @ret NULL		No console device has input available.
- * @err None
+ * @err None		-
  *
  * All enabled console devices are checked once for available input
  * using each device's console_driver::iskey() method.  The first
@@ -62,9 +62,9 @@ static struct console_driver * has_input ( void ) {
 /**
  * Read a single character from any console.
  *
- * @v None
+ * @v None		-
  * @ret character	Character read from a console.
- * @err None
+ * @err None		-
  *
  * A character will be read from the first enabled console device that
  * has input available using that console's console_driver::getchar()
@@ -112,10 +112,10 @@ int getchar ( void ) {
 
 /** Check for available input on any console.
  *
- * @v None
+ * @v None		-
  * @ret True		Input is available on a console
  * @ret False		Input is not available on any console
- * @err None
+ * @err None		-
  *
  * All enabled console devices are checked once for available input
  * using each device's console_driver::iskey() method.  If any console

src/core/vsprintf.c

@@ -20,7 +20,7 @@
  * @v args		Arguments corresponding to the format string
  * @ret len		Length of string written to buffer (if buf != NULL)
  * @ret	0		(if buf == NULL)
- * @err None
+ * @err None		-
  *
  * If #buf==NULL, then the string will be written to the console
  * directly using putchar().
@@ -157,7 +157,7 @@ static int vsprintf(char *buf, const char *fmt, va_list args)
  * @v ...		Arguments corresponding to the format string
  * @ret len		Length of string written to buffer (if buf != NULL)
  * @ret	0		(if buf == NULL)
- * @err None
+ * @err None		-
  *
  * If #buf==NULL, then the string will be written to the console
  * directly using putchar().
@@ -178,8 +178,8 @@ int sprintf(char *buf, const char *fmt, ...)
  *
  * @v fmt		Format string
  * @v ...		Arguments corresponding to the format string
- * @ret	None
- * @err None
+ * @ret	None		-
+ * @err None		-
  *
  */
 void printf(const char *fmt, ...)