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This document describes the Fortran 90 interface to the netCDF library. It applies to netCDF version 4.0. This document was last updated in 27 June 2008.
For a complete description of the netCDF format and utilities see The NetCDF Users Guide (The NetCDF Users Guide).
--- The Detailed Node Listing ---
Use of the NetCDF Library
Datasets
Groups
Dimensions
User Defined Data Types
Example
Compound Types Introduction
Variable Length Array Introduction
Opaque Type Introduction
Example
Enum Type Introduction
Variables
Attributes
You can use the netCDF library without knowing about all of the netCDF interface. If you are creating a netCDF dataset, only a handful of routines are required to define the necessary dimensions, variables, and attributes, and to write the data to the netCDF dataset. (Even less are needed if you use the ncgen utility to create the dataset before running a program using netCDF library calls to write data. See ncgen (NetCDF Users Guide).) Similarly, if you are writing software to access data stored in a particular netCDF object, only a small subset of the netCDF library is required to open the netCDF dataset and access the data. Authors of generic applications that access arbitrary netCDF datasets need to be familiar with more of the netCDF library.
In this chapter we provide templates of common sequences of netCDF calls needed for common uses. For clarity we present only the names of routines; omit declarations and error checking; omit the type-specific suffixes of routine names for variables and attributes; indent statements that are typically invoked multiple times; and use ... to represent arbitrary sequences of other statements. Full parameter lists are described in later chapters.
Here is a typical sequence of netCDF calls used to create a new netCDF dataset:
NF90_CREATE ! create netCDF dataset: enter define mode
...
NF90_DEF_DIM ! define dimensions: from name and length
...
NF90_DEF_VAR ! define variables: from name, type, dims
...
NF90_PUT_ATT ! assign attribute values
...
NF90_ENDDEF ! end definitions: leave define mode
...
NF90_PUT_VAR ! provide values for variable
...
NF90_CLOSE ! close: save new netCDF dataset
Only one call is needed to create a netCDF dataset, at which point you will be in the first of two netCDF modes. When accessing an open netCDF dataset, it is either in define mode or data mode. In define mode, you can create dimensions, variables, and new attributes, but you cannot read or write variable data. In data mode, you can access data and change existing attributes, but you are not permitted to create new dimensions, variables, or attributes.
One call to NF90_DEF_DIM is needed for each dimension created. Similarly, one call to NF90_DEF_VAR is needed for each variable creation, and one call to a member of the NF90_PUT_ATT family is needed for each attribute defined and assigned a value. To leave define mode and enter data mode, call NF90_ENDDEF.
Once in data mode, you can add new data to variables, change old values, and change values of existing attributes (so long as the attribute changes do not require more storage space). Data of all types is written to a netCDF variable using the NF90_PUT_VAR subroutine. Single values, arrays, or array sections may be supplied to NF90_PUT_VAR; optional arguments allow the writing of subsampled or mapped portions of the variable. (Subsampled and mapped access are general forms of data access that are explained later.)
Finally, you should explicitly close all netCDF datasets that have been opened for writing by calling NF90_CLOSE. By default, access to the file system is buffered by the netCDF library. If a program terminates abnormally with netCDF datasets open for writing, your most recent modifications may be lost. This default buffering of data is disabled by setting the NF90_SHARE flag when opening the dataset. But even if this flag is set, changes to attribute values or changes made in define mode are not written out until NF90_SYNC or NF90_CLOSE is called.
Here we consider the case where you know the names of not only the netCDF datasets, but also the names of their dimensions, variables, and attributes. (Otherwise you would have to do "inquire" calls.) The order of typical C calls to read data from those variables in a netCDF dataset is:
NF90_OPEN ! open existing netCDF dataset
...
NF90_INQ_DIMID ! get dimension IDs
...
NF90_INQ_VARID ! get variable IDs
...
NF90_GET_ATT ! get attribute values
...
NF90_GET_VAR ! get values of variables
...
NF90_CLOSE ! close netCDF dataset
First, a single call opens the netCDF dataset, given the dataset name, and returns a netCDF ID that is used to refer to the open netCDF dataset in all subsequent calls.
Next, a call to NF90_INQ_DIMID for each dimension of interest gets the dimension ID from the dimension name. Similarly, each required variable ID is determined from its name by a call to NF90_INQ_VARID. Once variable IDs are known, variable attribute values can be retrieved using the netCDF ID, the variable ID, and the desired attribute name as input to NF90_GET_ATT for each desired attribute. Variable data values can be directly accessed from the netCDF dataset with calls to NF90_GET_VAR.
Finally, the netCDF dataset is closed with NF90_CLOSE. There is no need to close a dataset open only for reading.
It is possible to write programs (e.g., generic software) which do such things as processing every variable, without needing to know in advance the names of these variables. Similarly, the names of dimensions and attributes may be unknown.
Names and other information about netCDF objects may be obtained from netCDF datasets by calling inquire functions. These return information about a whole netCDF dataset, a dimension, a variable, or an attribute. The following template illustrates how they are used:
NF90_OPEN ! open existing netCDF dataset
...
NF90_INQUIRE ! find out what is in it
...
NF90_INQUIRE_DIMENSION ! get dimension names, lengths
...
NF90_INQUIRE_VARIABLE ! get variable names, types, shapes
...
NF90_INQ_ATTNAME ! get attribute names
...
NF90_INQUIRE_ATTRIBUTE ! get other attribute information
...
NF90_GET_ATT ! get attribute values
...
NF90_GET_VAR ! get values of variables
...
NF90_CLOSE ! close netCDF dataset
As in the previous example, a single call opens the existing netCDF dataset, returning a netCDF ID. This netCDF ID is given to the NF90_INQUIRE routine, which returns the number of dimensions, the number of variables, the number of global attributes, and the ID of the unlimited dimension, if there is one.
All the inquire functions are inexpensive to use and require no I/O, since the information they provide is stored in memory when a netCDF dataset is first opened.
Dimension IDs use consecutive integers, beginning at 1. Also dimensions, once created, cannot be deleted. Therefore, knowing the number of dimension IDs in a netCDF dataset means knowing all the dimension IDs: they are the integers 1, 2, 3, ...up to the number of dimensions. For each dimension ID, a call to the inquire function NF90_INQUIRE_DIMENSION returns the dimension name and length.
Variable IDs are also assigned from consecutive integers 1, 2, 3, ... up to the number of variables. These can be used in NF90_INQUIRE_VARIABLE calls to find out the names, types, shapes, and the number of attributes assigned to each variable.
Once the number of attributes for a variable is known, successive calls to NF90_INQ_ATTNAME return the name for each attribute given the netCDF ID, variable ID, and attribute number. Armed with the attribute name, a call to NF90_INQUIRE_ATTRIBUTE returns its type and length. Given the type and length, you can allocate enough space to hold the attribute values. Then a call to NF90_GET_ATT returns the attribute values.
Once the IDs and shapes of netCDF variables are known, data values can be accessed by calling NF90_GET_VAR.
With write access to an existing netCDF dataset, you can overwrite data values in existing variables or append more data to record variables along the unlimited (record) dimension. To append more data to non-record variables requires changing the shape of such variables, which means creating a new netCDF dataset, defining new variables with the desired shape, and copying data. The netCDF data model was not designed to make such "schema changes" efficient or easy, so it is best to specify the shapes of variables correctly when you create a netCDF dataset, and to anticipate which variables will later grow by using the unlimited dimension in their definition.
The following code template lists a typical sequence of calls to overwrite some existing values and add some new records to record variables in an existing netCDF dataset with known variable names:
NF90_OPEN ! open existing netCDF dataset
...
NF90_INQ_VARID ! get variable IDs
...
NF90_PUT_VAR ! provide new values for variables, if any
...
NF90_PUT_ATT ! provide new values for attributes, if any
...
NF90_CLOSE ! close netCDF dataset
A netCDF dataset is first opened by the NF90_OPEN call. This call puts the open dataset in data mode, which means existing data values can be accessed and changed, existing attributes can be changed, but no new dimensions, variables, or attributes can be added.
Next, calls to NF90_INQ_VARID get the variable ID from the name, for each variable you want to write. Then each call to NF90_PUT_VAR writes data into a specified variable, either a single value at a time, or a whole set of values at a time, depending on which variant of the interface is used. The calls used to overwrite values of non-record variables are the same as are used to overwrite values of record variables or append new data to record variables. The difference is that, with record variables, the record dimension is extended by writing values that don't yet exist in the dataset. This extends all record variables at once, writing "fill values" for record variables for which the data has not yet been written (but see Fill Values to specify different behavior).
Calls to NF90_PUT_ATT may be used to change the values of existing attributes, although data that changes after a file is created is typically stored in variables rather than attributes.
Finally, you should explicitly close any netCDF datasets into which data has been written by calling NF90_CLOSE before program termination. Otherwise, modifications to the dataset may be lost.
An existing netCDF dataset can be extensively altered. New dimensions, variables, and attributes can be added or existing ones renamed, and existing attributes can be deleted. Existing dimensions, variables, and attributes can be renamed. The following code template lists a typical sequence of calls to add new netCDF components to an existing dataset:
NF90_OPEN ! open existing netCDF dataset
...
NF90_REDEF ! put it into define mode
...
NF90_DEF_DIM ! define additional dimensions (if any)
...
NF90_DEF_VAR ! define additional variables (if any)
...
NF90_PUT_ATT ! define other attributes (if any)
...
NF90_ENDDEF ! check definitions, leave define mode
...
NF90_PUT_VAR ! provide new variable values
...
NF90_CLOSE ! close netCDF dataset
A netCDF dataset is first opened by the NF90_OPEN call. This call puts the open dataset in data mode, which means existing data values can be accessed and changed, existing attributes can be changed (so long as they do not grow), but nothing can be added. To add new netCDF dimensions, variables, or attributes you must enter define mode, by calling NF90_REDEF. In define mode, call NF90_DEF_DIM to define new dimensions, NF90_DEF_VAR to define new variables, and NF90_PUT_ATT to assign new attributes to variables or enlarge old attributes.
You can leave define mode and reenter data mode, checking all the new definitions for consistency and committing the changes to disk, by calling NF90_ENDDEF. If you do not wish to reenter data mode, just call NF90_CLOSE, which will have the effect of first calling NF90_ENDDEF.
Until the NF90_ENDDEF call, you may back out of all the redefinitions made in define mode and restore the previous state of the netCDF dataset by calling NF90_ABORT. You may also use the NF90_ABORT call to restore the netCDF dataset to a consistent state if the call to NF90_ENDDEF fails. If you have called NF90_CLOSE from definition mode and the implied call to NF90_ENDDEF fails, NF90_ABORT will automatically be called to close the netCDF dataset and leave it in its previous consistent state (before you entered define mode).
At most one process should have a netCDF dataset open for writing at one time. The library is designed to provide limited support for multiple concurrent readers with one writer, via disciplined use of the NF90_SYNC function and the NF90_SHARE flag. If a writer makes changes in define mode, such as the addition of new variables, dimensions, or attributes, some means external to the library is necessary to prevent readers from making concurrent accesses and to inform readers to call NF90_SYNC before the next access.
The netCDF library provides the facilities needed to handle errors in a flexible way. Each netCDF function returns an integer status value. If the returned status value indicates an error, you may handle it in any way desired, from printing an associated error message and exiting to ignoring the error indication and proceeding (not recommended!). For simplicity, the examples in this guide check the error status and call a separate function to handle any errors.
The NF90_STRERROR function is available to convert a returned integer error status into an error message string.
Occasionally, low-level I/O errors may occur in a layer below the netCDF library. For example, if a write operation causes you to exceed disk quotas or to attempt to write to a device that is no longer available, you may get an error from a layer below the netCDF library, but the resulting write error will still be reflected in the returned status value.
Details of how to compile and link a program that uses the netCDF C or Fortran interfaces differ, depending on the operating system, the available compilers, and where the netCDF library and include files are installed.
Every Fortran 90 procedure or module which references netCDF constants or procedures must have access to the module information created when the netCDF module was compiled. The suffix for this file is “MOD” (or sometimes “mod”).
Most F90 compilers allow the user to specify the location of .MOD files, usually with the -I flag. (Some compilers, like absoft, use -p instead).
f90 -c -I/usr/local/include mymodule.f90
Starting with version 3.6.2, another method of building the netCDF fortran libraries becomes available. With the –enable-separate-fortran option to configure, the user can specify that the C library should not contain the fortran functions. In these cases an additional library, libnetcdff.a (not the extra “f”) will be built. This library contains the fortran functions.
For more information about configure options, See Specifying the Environment for Building (The NetCDF Installation and Porting Guide).
Building separate fortran libraries is required for shared library builds, but is not done, by default, for static library builds.
When linking fortran programs without a separate fortran library, programs must link to the netCDF library like this:
f90 -o myprogram myprogram.o -L/usr/local/netcdf/lib -lnetcdf
This chapter presents the interfaces of the netCDF functions that deal with a netCDF dataset or the whole netCDF library.
A netCDF dataset that has not yet been opened can only be referred to by its dataset name. Once a netCDF dataset is opened, it is referred to by a netCDF ID, which is a small nonnegative integer returned when you create or open the dataset. A netCDF ID is much like a file descriptor in C or a logical unit number in FORTRAN. In any single program, the netCDF IDs of distinct open netCDF datasets are distinct. A single netCDF dataset may be opened multiple times and will then have multiple distinct netCDF IDs; however at most one of the open instances of a single netCDF dataset should permit writing. When an open netCDF dataset is closed, the ID is no longer associated with a netCDF dataset.
Functions that deal with the netCDF library include:
The operations supported on a netCDF dataset as a single object are:
Each interface description for a particular netCDF function in this and later chapters contains:
The examples follow a simple convention for error handling, always checking the error status returned from each netCDF function call and calling a handle_error function in case an error was detected. For an example of such a function, see Section 5.2 "Get error message corresponding to error status: nc_strerror".
The function NF90_STRERROR returns a static reference to an error message string corresponding to an integer netCDF error status or to a system error number, presumably returned by a previous call to some other netCDF function. The list of netCDF error status codes is available in the appropriate include file for each language binding.
function nf90_strerror(ncerr)
integer, intent( in) :: ncerr
character(len = 80) :: nf90_strerror
NCERRIf you provide an invalid integer error status that does not correspond to any netCDF error message or or to any system error message (as understood by the system strerror function), NF90_STRERROR returns a string indicating that there is no such error status.
Here is an example of a simple error handling function that uses NF90_STRERROR to print the error message corresponding to the netCDF error status returned from any netCDF function call and then exit:
subroutine handle_err(status)
integer, intent ( in) :: status
if(status /= nf90_noerr) then
print *, trim(nf90_strerror(status))
stop "Stopped"
end if
end subroutine handle_err
The function NF90_INQ_LIBVERS returns a string identifying the version of the netCDF library, and when it was built.
function nf90_inq_libvers()
character(len = 80) :: nf90_inq_libvers
This function takes no arguments, and returns no error status.
Here is an example using nc_inq_libvers to print the version of the netCDF library with which the program is linked:
print *, trim(nf90_inq_libvers())
This function creates a new netCDF dataset, returning a netCDF ID that can subsequently be used to refer to the netCDF dataset in other netCDF function calls. The new netCDF dataset opened for write access and placed in define mode, ready for you to add dimensions, variables, and attributes.
A creation mode flag specifies whether to overwrite any existing dataset with the same name and whether access to the dataset is shared.
function nf90_create(path, cmode, ncid)
character (len = *), intent(in ) :: path
integer, intent(in ) :: cmode
integer, optional, intent(in ) :: initialsize
integer, optional, intent(inout) :: chunksize
integer, intent( out) :: ncid
integer :: nf90_create
pathcmodeA zero value (defined for convenience as NF90_CLOBBER) specifies the default behavior: overwrite any existing dataset with the same file name and buffer and cache accesses for efficiency. The dataset will be in netCDF classic format. See NetCDF Classic Format Limitations (NetCDF Users' Guide).
Setting NF90_NOCLOBBER means you do not want to clobber (overwrite) an existing dataset; an error (NF90_EEXIST) is returned if the specified dataset already exists.
The NF90_SHARE flag is appropriate when one process may be writing the dataset and one or more other processes reading the dataset concurrently; it means that dataset accesses are not buffered and caching is limited. Since the buffering scheme is optimized for sequential access, programs that do not access data sequentially may see some performance improvement by setting the NF90_SHARE flag. (This only applies to netCDF-3 classic or 64-bit offset files.)
Setting NF90_64BIT_OFFSET causes netCDF to create a 64-bit offset format file, instead of a netCDF classic format file. The 64-bit offset format imposes far fewer restrictions on very large (i.e. over 2 GB) data files. See Large File Support (NetCDF Users' Guide).
Setting the NF90_HDF5 flag causes netCDF to create a netCDF-4/HDF5 format output file.
Oring the NF90_CLASSIC_MODEL flag with the NF90_HDF5 flag causes the
resulting netCDF-4/HDF5 file to restrict itself to the classic model -
none of the new netCDF-4 data model features, such as groups or
user-defined types, are allowed in such a file.
ncidThe following optional arguments allow additional performance tuning.
initialsizechunksizeThe library chooses a system-dependent default value if NF90_SIZEHINT_DEFAULT is supplied as input. If the "preferred I/O block size" is available from the stat() system call as member st_blksize this value is used. Lacking that, twice the system pagesize is used. Lacking a call to discover the system pagesize, the default chunksize is set to 8192 bytes.
The chunksize is a property of a given open netcdf descriptor ncid, it is not a persistent property of the netcdf dataset.
This is ignored for NetCDF-4/HDF5 files.
NF90_CREATE returns the value NF90_NOERR if no errors occurred. Possible causes of errors include:
In this example we create a netCDF dataset named foo.nc; we want the dataset to be created in the current directory only if a dataset with that name does not already exist:
use netcdf
implicit none
integer :: ncid, status
...
status = nf90_create(path = "foo.nc", cmode = nf90_noclobber, ncid = ncid)
if (status /= nf90_noerr) call handle_err(status)
The function NF90_OPEN opens an existing netCDF dataset for access.
function nf90_open(path, mode, ncid, chunksize)
character (len = *), intent(in ) :: path
integer, intent(in ) :: mode
integer, intent( out) :: ncid
integer, optional, intent(inout) :: chunksize
integer :: nf90_open
pathomodeOtherwise, the creation mode is NF90_WRITE, NF90_SHARE, or
NF90_WRITE|NF90_SHARE. Setting the NF90_WRITE flag opens the dataset with
read-write access. ("Writing" means any kind of change to the dataset,
including appending or changing data, adding or renaming dimensions,
variables, and attributes, or deleting attributes.) The NF90_SHARE flag
is appropriate when one process may be writing the dataset and one or
more other processes reading the dataset concurrently; it means that
dataset accesses are not buffered and caching is limited. Since the
buffering scheme is optimized for sequential access, programs that do
not access data sequentially may see some performance improvement by
setting the NF90_SHARE flag.
ncidThe following optional argument allows additional performance tuning.
chunksizeThe library chooses a system-dependent default value if NF90_SIZEHINT_DEFAULT is supplied as input. If the "preferred I/O block size" is available from the stat() system call as member st_blksize this value is used. Lacking that, twice the system pagesize is used. Lacking a call to discover the system pagesize, the default chunksize is set to 8192 bytes.
The chunksize is a property of a given open netcdf descriptor ncid, it is not a persistent property of the netcdf dataset.
NF90_OPEN returns the value NF90_NOERR if no errors occurred. Otherwise, the returned status indicates an error. Possible causes of errors include:
Here is an example using NF90_OPEN to open an existing netCDF dataset named foo.nc for read-only, non-shared access:
use netcdf
implicit none
integer :: ncid, status
...
status = nf90_open(path = "foo.nc", cmode = nf90_nowrite, ncid = ncid)
if (status /= nf90_noerr) call handle_err(status)
The function NF90_REDEF puts an open netCDF dataset into define mode, so dimensions, variables, and attributes can be added or renamed and attributes can be deleted.
function nf90_redef(ncid)
integer, intent( in) :: ncid
integer :: nf90_redef
ncidNF90_REDEF returns the value NF90_NOERR if no errors occurred. Otherwise, the returned status indicates an error. Possible causes of errors include:
Here is an example using NF90_REDEF to open an existing netCDF dataset named foo.nc and put it into define mode:
use netcdf
implicit none
integer :: ncid, status
...
status = nf90_open("foo.nc", nf90_write, ncid) ! Open dataset
if (status /= nf90_noerr) call handle_err(status)
...
status = nf90_redef(ncid) ! Put the file in define mode
if (status /= nf90_noerr) call handle_err(status)
The function NF90_ENDDEF takes an open netCDF dataset out of define mode. The changes made to the netCDF dataset while it was in define mode are checked and committed to disk if no problems occurred. Non-record variables may be initialized to a "fill value" as well (see NF90_SET_FILL). The netCDF dataset is then placed in data mode, so variable data can be read or written.
This call may involve copying data under some circumstances. For a more extensive discussion See File Structure and Performance (NetCDF Users Guide).
function nf90_enddef(ncid, h_minfree, v_align, v_minfree, r_align)
integer, intent( in) :: ncid
integer, optional, intent( in) :: h_minfree, v_align, v_minfree, r_align
integer :: nf90_enddef
ncidThe following arguments allow additional performance tuning. Note: these arguments expose internals of the netcdf version 1 file format, and may not be available in future netcdf implementations.
The current netcdf file format has three sections: the "header" section, the data section for fixed size variables, and the data section for variables which have an unlimited dimension (record variables). The header begins at the beginning of the file. The index (offset) of the beginning of the other two sections is contained in the header. Typically, there is no space between the sections. This causes copying overhead to accrue if one wishes to change the size of the sections, as may happen when changing the names of things, text attribute values, adding attributes or adding variables. Also, for buffered i/o, there may be advantages to aligning sections in certain ways.
The minfree parameters allow one to control costs of future calls to nf90_redef or nf90_enddef by requesting that some space be available at the end of the section. The default value for both h_minfree and v_minfree is 0.
The align parameters allow one to set the alignment of the beginning of the corresponding sections. The beginning of the section is rounded up to an index which is a multiple of the align parameter. The flag value NF90_ALIGN_CHUNK tells the library to use the chunksize (see above) as the align parameter. The default value for both v_align and r_align is 4 bytes.
h_minfreev_minfreev_alignr_alignNF90_ENDDEF returns the value NF90_NOERR if no errors occurred. Otherwise, the returned status indicates an error. Possible causes of errors include:
Here is an example using NF90_ENDDEF to finish the definitions of a new netCDF dataset named foo.nc and put it into data mode:
use netcdf
implicit none
integer :: ncid, status
...
status = nf90_create("foo.nc", nf90_noclobber, ncid)
if (status /= nf90_noerr) call handle_err(status)
... ! create dimensions, variables, attributes
status = nf90_enddef(ncid)
if (status /= nf90_noerr) call handle_err(status)
The function NF90_CLOSE closes an open netCDF dataset. If the dataset is in define mode, NF90_ENDDEF will be called before closing. (In this case, if NF90_ENDDEF returns an error, NF90_ABORT will automatically be called to restore the dataset to the consistent state before define mode was last entered.) After an open netCDF dataset is closed, its netCDF ID may be reassigned to the next netCDF dataset that is opened or created.
function nf90_close(ncid)
integer, intent( in) :: ncid
integer :: nf90_close
ncidNF90_CLOSE returns the value NF90_NOERR if no errors occurred. Otherwise, the returned status indicates an error. Possible causes of errors include:
Here is an example using NF90_CLOSE to finish the definitions of a new netCDF dataset named foo.nc and release its netCDF ID:
use netcdf
implicit none
integer :: ncid, status
...
status = nf90_create("foo.nc", nf90_noclobber, ncid)
if (status /= nf90_noerr) call handle_err(status)
... ! create dimensions, variables, attributes
status = nf90_close(ncid)
if (status /= nf90_noerr) call handle_err(status)
The NF90_INQUIRE subroutine returns information about an open netCDF dataset, given its netCDF ID. The subroutine can be called from either define mode or data mode, and returns values for any or all of the following: the number of dimensions, the number of variables, the number of global attributes, and the dimension ID of the dimension defined with unlimited length, if any. An additional function, NF90_INQ_FORMAT, returns the (rarely needed) format version.
No I/O is performed when NF90_INQUIRE is called, since the required information is available in memory for each open netCDF dataset.
function nf90_inquire(ncid, nDimensions, nVariables, nAttributes, &
unlimitedDimId, formatNum)
integer, intent( in) :: ncid
integer, optional, intent(out) :: nDimensions, nVariables, &
nAttributes, unlimitedDimId, &
formatNum
integer :: nf90_inquire
ncidnDimensionsnVariablesnAttributesunlimitedDimIDformatFunction NF90_INQUIRE returns the value NF90_NOERR if no errors occurred. Otherwise, the returned status indicates an error. Possible causes of errors include:
Here is an example using NF90_INQUIRE to find out about a netCDF dataset named foo.nc:
use netcdf
implicit none
integer :: ncid, status, nDims, nVars, nGlobalAtts, unlimDimID
...
status = nf90_open("foo.nc", nf90_nowrite, ncid)
if (status /= nf90_noerr) call handle_err(status)
...
status = nf90_inquire(ncid, nDims, nVars, nGlobalAtts, unlimdimid)
if (status /= nf90_noerr) call handle_err(status)
status = nf90_inquire(ncid, nDimensions = nDims, &
unlimitedDimID = unlimdimid)
if (status /= nf90_noerr) call handle_err(status)
The function NF90_SYNC offers a way to synchronize the disk copy of a netCDF dataset with in-memory buffers. There are two reasons you might want to synchronize after writes:
This function is backward-compatible with previous versions of the netCDF library. The intent was to allow sharing of a netCDF dataset among multiple readers and one writer, by having the writer call NF90_SYNC after writing and the readers call NF90_SYNC before each read. For a writer, this flushes buffers to disk. For a reader, it makes sure that the next read will be from disk rather than from previously cached buffers, so that the reader will see changes made by the writing process (e.g., the number of records written) without having to close and reopen the dataset. If you are only accessing a small amount of data, it can be expensive in computer resources to always synchronize to disk after every write, since you are giving up the benefits of buffering.
An easier way to accomplish sharing (and what is now recommended) is to have the writer and readers open the dataset with the NF90_SHARE flag, and then it will not be necessary to call NF90_SYNC at all. However, the NF90_SYNC function still provides finer granularity than the NF90_SHARE flag, if only a few netCDF accesses need to be synchronized among processes.
It is important to note that changes to the ancillary data, such as attribute values, are not propagated automatically by use of the NF90_SHARE flag. Use of the NF90_SYNC function is still required for this purpose.
Sharing datasets when the writer enters define mode to change the data schema requires extra care. In previous releases, after the writer left define mode, the readers were left looking at an old copy of the dataset, since the changes were made to a new copy. The only way readers could see the changes was by closing and reopening the dataset. Now the changes are made in place, but readers have no knowledge that their internal tables are now inconsistent with the new dataset schema. If netCDF datasets are shared across redefinition, some mechanism external to the netCDF library must be provided that prevents access by readers during redefinition and causes the readers to call NF90_SYNC before any subsequent access.
When calling NF90_SYNC, the netCDF dataset must be in data mode. A netCDF dataset in define mode is synchronized to disk only when NF90_ENDDEF is called. A process that is reading a netCDF dataset that another process is writing may call NF90_SYNC to get updated with the changes made to the data by the writing process (e.g., the number of records written), without having to close and reopen the dataset.
Data is automatically synchronized to disk when a netCDF dataset is closed, or whenever you leave define mode.
function nf90_sync(ncid)
integer, intent( in) :: ncid
integer :: nf90_sync
ncidNF90_SYNC returns the value NF90_NOERR if no errors occurred. Otherwise, the returned status indicates an error. Possible causes of errors include:
Here is an example using NF90_SYNC to synchronize the disk writes of a netCDF dataset named foo.nc:
use netcdf
implicit none
integer :: ncid, status
...
status = nf90_open("foo.nc", nf90_write, ncid)
if (status /= nf90_noerr) call handle_err(status)
...
! write data or change attributes
...
status = NF90_SYNC(ncid)
if (status /= nf90_noerr) call handle_err(status)
You no longer need to call this function, since it is called automatically by NF90_CLOSE in case the dataset is in define mode and something goes wrong with committing the changes. The function NF90_ABORT just closes the netCDF dataset, if not in define mode. If the dataset is being created and is still in define mode, the dataset is deleted. If define mode was entered by a call to NF90_REDEF, the netCDF dataset is restored to its state before definition mode was entered and the dataset is closed.
function nf90_abort(ncid)
integer, intent( in) :: ncid
integer :: nf90_abort
ncidNF90_ABORT returns the value NF90_NOERR if no errors occurred. Otherwise, the returned status indicates an error. Possible causes of errors include:
Here is an example using NF90_ABORT to back out of redefinitions of a dataset named foo.nc:
use netcdf
implicit none
integer :: ncid, status, LatDimID
...
status = nf90_open("foo.nc", nf90_write, ncid)
if (status /= nf90_noerr) call handle_err(status)
...
status = nf90_redef(ncid)
if (status /= nf90_noerr) call handle_err(status)
...
status = nf90_def_dim(ncid, "Lat", 18, LatDimID)
if (status /= nf90_noerr) then ! Dimension definition failed
call handle_err(status)
status = nf90_abort(ncid) ! Abort redefinitions
if (status /= nf90_noerr) call handle_err(status)
end if
...
This function is intended for advanced usage, to optimize writes under some circumstances described below. The function NF90_SET_FILL sets the fill mode for a netCDF dataset open for writing and returns the current fill mode in a return parameter. The fill mode can be specified as either NF90_FILL or NF90_NOFILL. The default behavior corresponding to NF90_FILL is that data is pre-filled with fill values, that is fill values are written when you create non-record variables or when you write a value beyond data that has not yet been written. This makes it possible to detect attempts to read data before it was written. See Fill Values, for more information on the use of fill values. See Attribute Conventions, for information about how to define your own fill values.
The behavior corresponding to NF90_NOFILL overrides the default behavior of prefilling data with fill values. This can be used to enhance performance, because it avoids the duplicate writes that occur when the netCDF library writes fill values that are later overwritten with data.
A value indicating which mode the netCDF dataset was already in is returned. You can use this value to temporarily change the fill mode of an open netCDF dataset and then restore it to the previous mode.
After you turn on NF90_NOFILL mode for an open netCDF dataset, you must be certain to write valid data in all the positions that will later be read. Note that nofill mode is only a transient property of a netCDF dataset open for writing: if you close and reopen the dataset, it will revert to the default behavior. You can also revert to the default behavior by calling NF90_SET_FILL again to explicitly set the fill mode to NF90_FILL.
There are three situations where it is advantageous to set nofill mode:
If the netCDF dataset has an unlimited dimension and the last record was written while in nofill mode, then the dataset may be shorter than if nofill mode was not set, but this will be completely transparent if you access the data only through the netCDF interfaces.
The use of this feature may not be available (or even needed) in future releases. Programmers are cautioned against heavy reliance upon this feature.
function nf90_set_fill(ncid, fillmode, old_mode)
integer, intent( in) :: ncid, fillmode
integer, intent(out) :: old_mode
integer :: nf90_set_fill
ncidfillmodeold_modeNF90_SET_FILL returns the value NF90_NOERR if no errors occurred. Otherwise, the returned status indicates an error. Possible causes of errors include:
Here is an example using NF90_SET_FILL to set nofill mode for subsequent writes of a netCDF dataset named foo.nc:
use netcdf
implicit none
integer :: ncid, status, oldMode
...
status = nf90_open("foo.nc", nf90_write, ncid)
if (status /= nf90_noerr) call handle_err(status)
...
! Write data with prefilling behavior
...
status = nf90_set_fill(ncid, nf90_nofill, oldMode)
if (status /= nf90_noerr) call handle_err(status)
...
! Write data with no prefilling
...
NetCDF-4 added support for hierarchical groups within netCDF datasets.
Groups are identified with a ncid, which identifies both the open file, and the group within that file. When a file is opened with NF90_OPEN or NF90_CREATE, the ncid for the root group of that file is provided. Using that as a starting point, users can add new groups, or list and navigate existing groups.
All netCDF calls take a ncid which determines where the call will take its action. For example, the NF90_DEF_VAR function takes a ncid as its first parameter. It will create a variable in whichever group its ncid refers to. Use the root ncid provided by NF90_CREATE or NF90_OPEN to create a variable in the root group. Or use NF90_DEF_GRP to create a group and use its ncid to define a variable in the new group.
Variable are only visible in the group in which they are defined. The same applies to attributes. “Global” attributes are defined in whichever group is refered to by the ncid.
Dimensions are visible in their groups, and all child groups.
Group operations are only permitted on netCDF-4 files - that is, files created with the HDF5 flag in nf90_create. (see NF90_CREATE). Groups are not compatible with the netCDF classic data model, so files created with the NC_CLASSIC_MODEL file cannot contain groups (except the root group).
Given an ncid and group name (NULL or "" gets root group), return ncid of the named group.
function nf90_inq_ncid(ncid, name, grp_ncid)
integer, intent(in) :: ncid
character (len = *), intent(in) :: name
integer, intent(out) :: grp_ncid
integer :: nf90_inq_ncid
NCIDNAMEGRPIDNF90_NOERRNF90_EBADIDNF90_ENOTNC4NF90_ESTRICTNC3NF90_EHDFERRThis example is from nf90_test/ftst_groups.F.
Given a location id, return the number of groups it contains, and an array of their ncids.
function nf90_inq_grps(ncid, numgrps, ncids)
integer, intent(in) :: ncid
integer, intent(out) :: numgrps
integer, intent(out) :: ncids
integer :: nf90_inq_grps
NCIDNUMGRPSNCIDSNF90_NOERRNF90_EBADIDNF90_ENOTNC4NF90_ESTRICTNC3NF90_EHDFERRFind all varids for a location.
function nf90_inq_varids(ncid, nvars, varids)
integer, intent(in) :: ncid
integer, intent(out) :: nvars
integer, intent(out) :: varids
integer :: nf90_inq_varids
NCIDVARIDSNF90_NOERRNF90_EBADIDNF90_ENOTNC4NF90_ESTRICTNC3NF90_EHDFERRFind all dimids for a location. This finds all dimensions in a group, or any of its parents.
function nf90_inq_dimids(ncid, ndims, dimids, include_parents)
integer, intent(in) :: ncid
integer, intent(out) :: ndims
integer, intent(out) :: dimids
integer, intent(out) :: include_parents
integer :: nf90_inq_dimids
NCIDDIMIDSINCLUDE_PARENTSNF90_NOERRNF90_EBADIDNF90_ENOTNC4NF90_ESTRICTNC3NF90_EHDFERRGiven ncid, find length of the full name. (Root group is named "/", with length 1.)
function nf90_inq_grpname_len(ncid, len)
integer, intent(in) :: ncid
integer, intent(out) :: len
integer :: nf90_inq_grpname_len
nf90_inq_grpname_len = nf_inq_grpname_len(ncid, len)
end function nf90_inq_grpname_len
NCIDLENNF90_NOERRNF90_EBADIDNF90_ENOTNC4NF90_ESTRICTNC3NF90_EHDFERRGiven ncid, find relative name of group. (Root group is named "/").
The name provided by this function is relative to the parent group. For a full path name for the group is, with all parent groups included, separated with a forward slash (as in Unix directory names) See NF90_INQ_GRPNAME_FULL.
function nf90_inq_grpname(ncid, name)
integer, intent(in) :: ncid
character (len = *), intent(out) :: name
integer :: nf90_inq_grpname
NCIDNAMENF90_NOERRNF90_EBADIDNF90_ENOTNC4NF90_ESTRICTNC3NF90_EHDFERRGiven ncid, find complete name of group. (Root group is named "/").
The name provided by this function is a full path name for the group is, with all parent groups included, separated with a forward slash (as in Unix directory names). For a name relative to the parent group See NF90_INQ_GRPNAME.
To find the length of the full name See NF90_INQ_GRPNAME_LEN.
function nf90_inq_grpname_full(ncid, len, name)
integer, intent(in) :: ncid
integer, intent(out) :: len
character (len = *), intent(out) :: name
integer :: nf90_inq_grpname_full
NCIDLENNAMENF90_NOERRNF90_EBADIDNF90_ENOTNC4NF90_ESTRICTNC3NF90_EHDFERRGiven ncid, find the ncid of the parent group.
When used with the root group, this function returns the NF90_ENOGRP error (since the root group has no parent.)
function nf90_inq_grp_parent(ncid, parent_ncid)
integer, intent(in) :: ncid
integer, intent(out) :: parent_ncid
integer :: nf90_inq_grp_parent
NCIDPARENT_NCIDNF90_NOERRNF90_EBADIDNF90_ENOGRPNF90_ENOTNC4NF90_ESTRICTNC3NF90_EHDFERRCreate a group. Its location id is returned in new_ncid.
function nf90_def_grp(parent_ncid, name, new_ncid)
integer, intent(in) :: parent_ncid
character (len = *), intent(in) :: name
integer, intent(out) :: new_ncid
integer :: nf90_def_grp
PARENT_NCIDNAMENEW_NCIDNF90_NOERRNF90_EBADIDNF90_ENAMEINUSENF90_EMAXNAMENF90_EBADNAMENF90_ENOTNC4NF90_ESTRICTNC3NF90_EHDFERRNF90_EPERMNF90_ENOTINDEFINE C Create the netCDF file.
retval = nf90_create(file_name, NF90_NETCDF4, ncid)
if (retval .ne. nf90_noerr) call handle_err(retval)
C Create a group and a subgroup.
retval = nf90_def_grp(ncid, group_name, grpid)
if (retval .ne. nf90_noerr) call handle_err(retval)
retval = nf90_def_grp(grpid, sub_group_name, sub_grpid)
if (retval .ne. nf90_noerr) call handle_err(retval)
Dimensions for a netCDF dataset are defined when it is created, while the netCDF dataset is in define mode. Additional dimensions may be added later by reentering define mode. A netCDF dimension has a name and a length. At most one dimension in a netCDF dataset can have the unlimited length, which means variables using this dimension can grow along this dimension.
There is a suggested limit (512) to the number of dimensions that can be defined in a single netCDF dataset. The limit is the value of the constant NF90_MAX_DIMS. The purpose of the limit is to make writing generic applications simpler. They need only provide an array of NF90_MAX_DIMS dimensions to handle any netCDF dataset. The implementation of the netCDF library does not enforce this advisory maximum, so it is possible to use more dimensions, if necessary, but netCDF utilities that assume the advisory maximums may not be able to handle the resulting netCDF datasets.
Ordinarily, the name and length of a dimension are fixed when the dimension is first defined. The name may be changed later, but the length of a dimension (other than the unlimited dimension) cannot be changed without copying all the data to a new netCDF dataset with a redefined dimension length.
A netCDF dimension in an open netCDF dataset is referred to by a small integer called a dimension ID. In the Fortran 90 interface, dimension IDs are 1, 2, 3, ..., in the order in which the dimensions were defined.
Operations supported on dimensions are:
The function NF90_DEF_DIM adds a new dimension to an open netCDF dataset in define mode. It returns (as an argument) a dimension ID, given the netCDF ID, the dimension name, and the dimension length. At most one unlimited length dimension, called the record dimension, may be defined for each netCDF dataset.
function nf90_def_dim(ncid, name, len, dimid)
integer, intent( in) :: ncid
character (len = *), intent( in) :: name
integer, intent( in) :: len
integer, intent(out) :: dimid
integer :: nf90_def_dim
ncidnamelendimidNF90_DEF_DIM returns the value NF90_NOERR if no errors occurred. Otherwise, the returned status indicates an error. Possible causes of errors include:
Here is an example using NF90_DEF_DIM to create a dimension named lat of length 18 and a unlimited dimension named rec in a new netCDF dataset named foo.nc:
use netcdf
implicit none
integer :: ncid, status, LatDimID, RecordDimID
...
status = nf90_create("foo.nc", nf90_noclobber, ncid)
if (status /= nf90_noerr) call handle_err(status)
...
status = nf90_def_dim(ncid, "Lat", 18, LatDimID)
if (status /= nf90_noerr) call handle_err(status)
status = nf90_def_dim(ncid, "Record", nf90_unlimited, RecordDimID)
if (status /= nf90_noerr) call handle_err(status)
The function NF90_INQ_DIMID returns (as an argument) the ID of a netCDF dimension, given the name of the dimension. If ndims is the number of dimensions defined for a netCDF dataset, each dimension has an ID between 1 and ndims.
function nf90_inq_dimid(ncid, name, dimid)
integer, intent( in) :: ncid
character (len = *), intent( in) :: name
integer, intent(out) :: dimid
integer :: nf90_inq_dimid
ncidnamedimidNF90_INQ_DIMID returns the value NF90_NOERR if no errors occurred. Otherwise, the returned status indicates an error. Possible causes of errors include:
Here is an example using NF90_INQ_DIMID to determine the dimension ID of a dimension named lat, assumed to have been defined previously in an existing netCDF dataset named foo.nc:
use netcdf
implicit none
integer :: ncid, status, LatDimID
...
status = nf90_open("foo.nc", nf90_nowrite, ncid)
if (status /= nf90_noerr) call handle_err(status)
...
status = nf90_inq_dimid(ncid, "Lat", LatDimID)
if (status /= nf90_noerr) call handle_err(status)
This function information about a netCDF dimension. Information about a dimension includes its name and its length. The length for the unlimited dimension, if any, is the number of records written so far.
function nf90_inquire_dimension(ncid, dimid, name, len)
integer, intent( in) :: ncid, dimid
character (len = *), optional, intent(out) :: name
integer, optional, intent(out) :: len
integer :: nf90_inquire_dimension
nciddimidnamelenThese functions return the value NF90_NOERR if no errors occurred. Otherwise, the returned status indicates an error. Possible causes of errors include:
Here is an example using NF90_INQ_DIM to determine the length of a dimension named lat, and the name and current maximum length of the unlimited dimension for an existing netCDF dataset named foo.nc:
use netcdf
implicit none
integer :: ncid, status, LatDimID, RecordDimID
integer :: nLats, nRecords
character(len = nf90_max_name) :: RecordDimName
...
status = nf90_open("foo.nc", nf90_nowrite, ncid)
if (status /= nf90_noerr) call handle_err(status)
! Get ID of unlimited dimension
status = nf90_inquire(ncid, unlimitedDimId = RecordDimID)
if (status /= nf90_noerr) call handle_err(status)
...
status = nf90_inq_dimid(ncid, "Lat", LatDimID)
if (status /= nf90_noerr) call handle_err(status)
! How many values of "lat" are there?
status = nf90_inquire_dimension(ncid, LatDimID, len = nLats)
if (status /= nf90_noerr) call handle_err(status)
! What is the name of the unlimited dimension, how many records are there?
status = nf90_inquire_dimension(ncid, RecordDimID, &
name = RecordDimName, len = Records)
if (status /= nf90_noerr) call handle_err(status)
The function NF90_RENAME_DIM renames an existing dimension in a netCDF dataset open for writing. If the new name is longer than the old name, the netCDF dataset must be in define mode. You cannot rename a dimension to have the same name as another dimension.
function nf90_rename_dim(ncid, dimid, name)
integer, intent( in) :: ncid
character (len = *), intent( in) :: name
integer, intent( in) :: dimid
integer :: nf90_rename_dim
nciddimidnameNF90_RENAME_DIM returns the value NF90_NOERR if no errors occurred. Otherwise, the returned status indicates an error. Possible causes of errors include:
Here is an example using NF90_RENAME_DIM to rename the dimension lat to latitude in an existing netCDF dataset named foo.nc:
use netcdf
implicit none
integer :: ncid, status, LatDimID
...
status = nf90_open("foo.nc", nf90_write, ncid)
if (status /= nf90_noerr) call handle_err(status)
...
! Put in define mode so we can rename the dimension
status = nf90_redef(ncid)
if (status /= nf90_noerr) call handle_err(status)
! Get the dimension ID for "Lat"...
status = nf90_inq_dimid(ncid, "Lat", LatDimID)
if (status /= nf90_noerr) call handle_err(status)
! ... and change the name to "Latitude".
status = nf90_rename_dim(ncid, LatDimID, "Latitude")
if (status /= nf90_noerr) call handle_err(status)
! Leave define mode
status = nf90_enddef(ncid)
if (status /= nf90_noerr) call handle_err(status)
NetCDF-4 has added support for four different user defined data types.
compound typevariable length array typeopaque typeenum typeUsers may construct user defined type with the various nf90_def_* functions described in this section. They may learn about user defined types by using the nf90_inq_ functions defined in this section.
Learn the number of types defined in a group, and their IDs.
function nf90_inq_typeids(ncid, ntypes, typeids)
integer, intent(in) :: ncid
integer, intent(out) :: ntypes
integer, intent(out) :: typeids
integer :: nf90_inq_typeids
NCIDNTYPESTYPEIDSNF90_NOERRNF90_BADIDGiven an ncid and a typeid, get the information about a type. This function will work on any type, including atomic and any user defined type, whether compound, opaque, enumeration, or variable length array.
For even more information about a user defined type NF90_INQ_USER_TYPE.
function nf90_inq_type(ncid, xtype, name, size, nfields)
integer, intent(in) :: ncid
integer, intent(in) :: xtype
character (len = *), intent(out) :: name
integer, intent(out) :: size
integer, intent(out) :: nfields
integer :: nf90_inq_type
NCIDXTYPENAMESIZEPNF90_NOERRNF90_EBADTYPEIDNF90_ENOTNC4NF90_ESTRICTNC3NF90_EBADGRPIDNF90_EBADIDNF90_EHDFERRGiven an ncid and a typeid, get the information about a user defined type. This function will work on any user defined type, whether compound, opaque, enumeration, or variable length array.
function nf90_inq_user_type(ncid, xtype, name, size, base_typeid, nfields, class)
integer, intent(in) :: ncid
integer, intent(in) :: xtype
character (len = *), intent(out) :: name
integer, intent(out) :: size
integer, intent(out) :: base_typeid
integer, intent(out) :: nfields
integer, intent(out) :: class
integer :: nf90_inq_user_type
NCIDXTYPENAMESIZEBASE_NF90_TYPENFIELDSCLASSNF90_NOERRNF90_EBADTYPEIDNF90_EBADFIELDIDNF90_EHDFERRUse this to set the element of the (potentially) n-dimensional array of VLEN. That is, this sets the data in one variable length array.
INTEGER FUNCTION NF90_PUT_VLEN_ELEMENT(INTEGER NCID, INTEGER XTYPE,
CHARACTER*(*) VLEN_ELEMENT, INTEGER LEN, DATA)
NCIDXTYPEVLEN_ELEMENTLENDATANF90_NOERRNF90_EBADTYPENF90_EBADIDNF90_EBADGRPIDThis example is from nf90_test/ftst_vars4.F.
C Set up the vlen with this helper function, since F77 can't deal
C with pointers.
retval = nf90_put_vlen_element(ncid, vlen_typeid, vlen,
& vlen_len, data1)
if (retval .ne. nf90_noerr) call handle_err(retval)
Use this to set the element of the (potentially) n-dimensional array of VLEN. That is, this sets the data in one variable length array.
INTEGER FUNCTION NF90_GET_VLEN_ELEMENT(INTEGER NCID, INTEGER XTYPE,
CHARACTER*(*) VLEN_ELEMENT, INTEGER LEN, DATA)
NCIDXTYPEVLEN_ELEMENTLENDATANF90_NOERRNF90_EBADTYPENF90_EBADIDNF90_EBADGRPIDNetCDF-4 added support for compound types, which allow users to construct a new type - a combination of other types, like a C struct.
Compound types are not supported in classic or 64-bit offset format files.
To write data in a compound type, first use nf90_def_compound to create the type, multiple calls to nf90_insert_compound to add to the compound type, and then write data with the appropriate nf90_put_var1, nf90_put_vara, nf90_put_vars, or nf90_put_varm call.
To read data written in a compound type, you must know its structure. Use the NF90_INQ_COMPOUND functions to learn about the compound type.
In Fortran a character buffer must be used for the compound data. The user must read the data from within that buffer in the same way that the C compiler which compiled netCDF would store the structure.
The use of compound types introduces challenges and portability issues for Fortran users.
Create a compound type. Provide an ncid, a name, and a total size (in bytes) of one element of the completed compound type.
After calling this function, fill out the type with repeated calls to NF90_INSERT_COMPOUND (see NF90_INSERT_COMPOUND). Call NF90_INSERT_COMPOUND once for each field you wish to insert into the compound type.
Note that there does not seem to be a fully portable way to read such types into structures in Fortran 90 (and there are no structures in Fortran 77). Dozens of top-notch programmers are swarming over this problem in a sub-basement of Unidata's giant underground bunker in Wyoming.
Fortran users may use character buffers to read and write compound types. User are invited to try classic Fortran features such as the equivilence and the common block statment.
function nf90_def_compound(ncid, size, name, typeid)
integer, intent(in) :: ncid
integer, intent(in) :: size
character (len = *), intent(in) :: name
integer, intent(out) :: typeid
integer :: nf90_def_compound
NCIDSIZENAMETYPEIDPNF90_NOERRNF90_EBADIDNF90_ENAMEINUSENF90_EMAXNAMENF90_EBADNAMENF90_ENOTNC4NF90_ESTRICTNC3NF90_EHDFERRNF90_EPERMNF90_ENOTINDEFINEInsert a named field into a compound type.
function nf90_insert_compound(ncid, xtype, name, offset, field_typeid)
integer, intent(in) :: ncid
integer, intent(in) :: xtype
character (len = *), intent(in) :: name
integer, intent(in) :: offset
integer, intent(in) :: field_typeid
integer :: nf90_insert_compound
TYPEIDNAMEOFFSET<