add note about new CDL header APIs

Author: wkliao

sneak_peek.md

@@ -27,7 +27,21 @@ This is essentially a placeholder for the next release note ...
   + none
 
 * New APIs
-  + none
+  + A set of APIs that read the header of a CDL file header and allow users to
+    query the metadata defined in the CDL file. These APIs can be useful for
+    creating a program (such as an I/O benchmark) based on an output netCDF
+    file from another application (a CDL file can be generated by running the
+    utility `ncmpidump/ncdump`). See
+    [PR #177](https://github.com/Parallel-NetCDF/PnetCDF/pull/177).
+    * `cdl_hdr_open()` opens and parses the CDL file's header
+    * `cdl_hdr_inq_format()` returns file format version
+    * `cdl_hdr_inq_ndims()` returns number of dimensions defined in CDL file
+    * `cdl_hdr_inq_dim()` returns metadata of a dimension
+    * `cdl_hdr_inq_nvars()` returns number of variables
+    * `cdl_hdr_inq_var()` returns metadata of a variable defined in CDL file
+    * `cdl_hdr_inq_nattrs()` returns number of attributes of a given variable
+    * `cdl_hdr_inq_attr()` returns metadata of an attribute
+    * `cdl_hdr_close()` closes the CDL file
 
 * API syntax changes
   + none
@@ -64,7 +78,8 @@ This is essentially a placeholder for the next release note ...
     See [PR #161](https://github.com/Parallel-NetCDF/PnetCDF/pull/161).
 
 * New example programs
-  + none
+  + examples/C/create_from_cdl.c shows how to call the new CDL header APIs to
+    create a netCDF file with the same metadata.
 
 * New programs for I/O benchmarks
   + WRF-IO contains an extraction of the I/O kernel of WRF (Wether Research
@@ -75,6 +90,7 @@ This is essentially a placeholder for the next release note ...
     See [PR #165](https://github.com/Parallel-NetCDF/PnetCDF/pull/165).
 
 * New test program
+  + test/cdf/tst_cdl_hdr_parser.c tests the new CDL header APIs.
   + test/testcases/tst_grow_header.c tests header extent growth by re-entering
     the define mode multiple times and add more fix-sized and record variables.