Fix asprintf bug

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3653 42af7a65-404d-4744-a932-0658087f49c3

TODO

@@ -1,4 +1,4 @@
-NuttX TODO List (Last updated May 28, 2011)
+NuttX TODO List (Last updated May 31, 2011)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 nuttx/
@@ -12,7 +12,7 @@ nuttx/
   (5)  Binary loaders (binfmt/)
  (15)  Network (net/, drivers/net)
   (2)  USB (drivers/usbdev, drivers/usbhost)
-  (5)  Libraries (lib/)
+  (6)  Libraries (lib/)
  (13)  File system/Generic drivers (fs/, drivers/)
   (1)  Graphics subystem (graphics/)
   (1)  Pascal add-on (pcode/)
@@ -386,6 +386,10 @@ o Libraries (lib/)
   Status:      Open
   Priority:    Low
 
+  Description: Not implemented: ferror() and clearerr()
+  Status:      Open
+  Priority:    Low
+
 o File system / Generic drivers (fs/, drivers/)
   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 

lib/stdio/lib_asprintf.c

@@ -101,6 +101,8 @@ int asprintf (FAR char **ptr, const char *fmt, ...)
   va_list ap;
   int     n;
 
+  DEBUGASSERT(ptr && fmt);
+
   /* First, use a nullstream to get the size of the buffer */
   
   lib_nulloutstream(&nulloutstream);
@@ -121,13 +123,19 @@ int asprintf (FAR char **ptr, const char *fmt, ...)
   lib_memoutstream((FAR struct lib_memoutstream_s *)&memoutstream,
                    buf, nulloutstream.nput);
 
-  /* Then let lib_vsprintf do it real thing */
+  /* Then let lib_vsprintf do it's real thing */
 
   va_start(ap, fmt);
   n = lib_vsprintf((FAR struct lib_outstream_s *)&memoutstream.public, fmt, ap);
   va_end(ap);
 
+  /* Terminate the string and return a pointer to the string to the caller.
+   * Hmmm.. looks like the memory would be stranded if lib_vsprintf() returned
+   * an error.  Does that ever happen?
+   */
+
   DEBUGASSERT(n < 0 || n == nulloutstream.nput);
   buf[nulloutstream.nput] = '\0';
+  *ptr = buf;
   return n;
 }