New features:

• Nonblocking requests now can be posted while the program is in the define mode. This feature enables applications to add new variables and post the nonblocking write requests without separating the codes by ncmpi_enddef(). Note ncmpi_wait_all and ncmpi_wait must still be called in the data mode.
• When using immutable write buffer in put APIs on a Little Endian machine, the in-place byte swap operation performed internally in PnetCDF can cause a fatal error (by trying to change the contents of an immutable memory space). The solution of copying user's write request to a temporary buffer and perform byte swap there conflicts with PnetCDF's design principle of avoiding internal memory allocation as much as possible. Since the size of immutable buffer in most cases is small, PnetCDF now compromise the two by making a copy of write requests that is less than 4KB. Users are warned that using immutable write buffer larger than 4KB will still cause the fatal error in the PnetCDF default configuration. The way to completely disable in-place byte swap is to build PnetCDF with --disable-in-place-swap option at the configure time. In this case, the internal memory allocation in PnetCDF will increase.

Syntax changes:

• In ncmpi_wait_all(), ncmpi_wait(), and ncmpi_cancel(), the API's third argument, array of requests IDs, is changed to INOUT. Upon successful completion or cancellation of individual nonblocking requests, the corresponding request IDs are set to NC_REQ_NULL.

New run-time environment variables:

• PNETCDF_VERBOSE_DEBUG_MODE environment variable can be used to print the location in the source code where the error code is originated, no matter the error is intended or not. This run-time environment variable only takes effect when PnetCDF is configure with debug mode, i.e. --enable-debug is used at the configure command line. Set this variable to 1 to enable. Set it to 0 or keep it unset disables this mode. Default is 0, i.e. disabled. Users are warned that enabling this mode may result in a lot of debugging messages printed in stderr.

New example programs:

• examples/C/nonblocking_write_in_def.c shows an example of posting nonblocking write requests in the define mode.
• examples/C/req_all.c shows an example of using NC_REQ_ALL to flush all pending nonblocking requests without providing the requests IDs.

New test program:

• test/cdf_format/dim_cdf12.c tests defining maximal dimension size for CDF-1 and CDF-2 file formats
• test/testcases/test_erange.c tests if the error code NC_ERANGE can be correctly returned for two cases 1) get a NC_UBYTE value of 255 from a netCDF file to a memory buffer of type signed char and 2) put a value of -1 of signed char to a NC_UBYTE variable in a netCDF file
• test/testcases/check_type.c tests if the error codes can be correctly returned when conflicted in-memory and extenal data types are used.
• test/testcases/put_parameter.f tests the use of immutable write buffer (e.g. a buffer declared as PARAMETER). Note the buffer size must be smaller than 4KB.
• test/nonblocking/i_varn_indef.c tests posting nonblocking requests in define mode.
• test/nonblocking/req_all.c tests the use of NC_REQ_ALL for flushing all pending nonblocking requests without providing the requests IDs.
• test/last_large_var.c tests the special case when there is no record variable, the last fixed-size variable can be larger than 2GiB in size if its starting file offset is less than 2GiB.
• test/testcases/buftype_free.c and test/testcases/buftype_freef.f test the bug in r2160.
• testcases/add_var.c checks the starting file offsets of newly added variables from re-entering the define mode.
• testcases/attrf.f checks NF_ERANGE is returned instead of coredump. This is particularly for NAG Fortran compiler that may report "Arithmetics exception".
• testcases/check_striping.c checks if the file striping unit and factor returned from MPI-IO hints are consistent among processes.
• test/nonblocking/column_wise.c checks if PnetCDF detects interleaved fileviews from multiple nonblocking requests and correctly breaks and reconstructs the fileviews so the combined fileview is monotonic non-decreasing in file offsets.

New optimization:

• Filling variables at ncmpi_enddef() is now done by aggregating all write requests into one MPI collective write call. In v 1.6.1, this is done by filling one variable at a time.

New utility program:

• ncoffsets reports the file offset information, including the starting and ending file offsets, of variables stored in a netCDF file. ncoffsets is compiled with gcc if gcc is presented on the build system. Additional command-line options are: (-v) reports only for a selected list of variables in interest, (-s) prints the variable sizes, (-g) outputs the file space gap size from the end of previous variable, (-x) reports whether there is a gap between any two adjacent fixed-size variables. See the man page for descriptions of all command-line options and examples.

Semantics updates:

• All nonblocking APIs now take a NULL pointer for the request ID argument, meaning users do not wish to keep track of the request ID. If NULL request IDs are used, NC_REQ_ALL should be used when calling ncmpi_wait_all/ncmpi_wait to commit all the pending nonblocking requests. This feature relinquishes users from the responsibility of tracking the IDs of pending requests.
• Using NC_REQ_ALL as the 2nd argument "num" in ncmpi_wait_all/ncmpi_wait APIs will flush all the pending nonblocking requests. In this case, the 3rd and 4th arguments "array_of_requests" and "array_of_statuses" will be ignored and thus these two arguments can be NULLs.
• Using NC_REQ_ALL in ncmpi_cancel() will cancel all the pending nonblocking requests.
• Using NC_GET_REQ_ALL or NC_PUT_REQ_ALL in ncmpi_wait_all(), ncmpi_wait(), and ncmpi_cancel() for all the pending get-only or put-only requests, respectively.

Other updates:

• Conform with netCDF on the maximal dimension size for CDF-2 file format to be (2³² - 4)
• NC_ERANGE checks have been removed from nc_test for text APIs and variables that are defined as NC_CHAR type
• Add README.K-Computer build recipe for using Fujitsu MPI compilers on the K computer at RIKEN in Japan
• Add README.INTEL build recipe for using Intel MPI compilers 4.x
• Build dependency rule is added for files configure and configure.in
• PnetCDF checks MPICC/MPICXX/MPIF77/MPIF90 instead of CC/CXX/F77/F90/FC. If MPICC/MPICXX/MPIF77/MPIF90 are set, PnetCDF will ignore CC/CXX/F77/F90/FC. If CC/CXX/F77/F90/FC is set instead of MPICC/MPICXX/MPIF77/MPIF90, PnetCDF will now copy them to MPICC/MPICXX/MPIF77/MPIF90.
• Enforce netCDF convention on error code priority: NC_ECHAR trumps NC_EINVALCOORDS, NC_EEDGE, and NC_ESTRIDE.
• Return error code NC_EGLOBAL instead of NC_ENOTVAR for APIs where using NC_GLOBAL as the variable ID argument is prohibited.
• All Fortran 77 test and example programs (files with .f and .F extensions) have been revised to conform with 77 standard, and was tested using pgf77.
• Now provides a pkg-config file (​http://www.freedesktop.org/wiki/Software/pkg-config/), making it slightly easier to set the correct pnetcdf include and library paths.

Bug fixes:

• Fix the bus error of invalid address alignment when build with Fujitsu compiler. See r2171 and r2180.
• Fix the bug for the special case when there is no record variable, the last fixed-size variable can be larger than 2GiB in size if its starting file offset is less than 2GiB. See r2166.
• Fix the nonblocking flexible APIs that fail to save (duplicate) the user MPI derived data type that later is needed to unpack read data to the user buffer (a call to MPI_Unpack). See r2160.
• Fix Fortran 77 constants nf_fill_uint and nf_fill_int64 (thanks Jim Edwards) that pgf77-based MPI compiler does not like "_8" modifier. See r2045 and r2051. The same issue for NAG Fortran compiler is also resolved. See r2089 and r2093.
• In the example program examples/tutorial/pnetcdf-write-nb.c, the write buffers used in two iput API calls should be different. See r2095.
• Fix the error reporting mechanism for NC_ERANGE, for when an arithmetic overflow happens. Overflow checking is now performed before I/O.