This manual describes the UDUNITS-2
package, which contains a C library for units of physical quantities and a unit-definition and value-conversion utility.
The UDUNITS-2
package provides support for units of physical quantities. Its three main components are:
udunits2lib
a C library for units of physical quantities;udunits2prog
a utility for obtaining the definition of a unit and for converting numeric values between compatible units; andUDUNITS-1
PackageThe UDUNIT-2
package differs from the UDUNITS-1
package in the following ways:
UDUNITS-1
package only supports the ASCII character set. The UDUNITS-2
package supports the following character sets: ASCII, ISO 8859-1 (Latin-1),
and the UTF-8 encoding of ISO 10646 (Unicode). This means that unit
string specifications like "µ°F·Ωâ»Â¹
" are now supported (your
viewer must support UTF-8 to display this string correctly).
0.1 lg(re 1 mW)
" specifies a deciBel unit with a
one milliwatt reference level.
Such units are fully integrated into the package and all meaningful
operations and conversions are supported.
float
, double
, or
one-dimensional arrays of float
s or double
s.
UDUNITS-1
package. The new interface, however, is easily
understood and easy to use. To support backward comptibility,
the package does contain a version 1 C API, which uses the version 2
library.
One thing that has not changed is that almost all unit string specifications
understood by the UDUNITS-1
package are also
understood by the UDUNITS-2
package. One exception is
the symbol g
, which in version 1 of the package was associated with
standard free fall (a unit of acceleration) but which is associated
with the unit gram in version 2 of the package.
Next: Library, Previous: Differences, Up: Top [Contents][Index]
• Prerequisites: | Prerequisites for this package | |
• Binary: | Installing from a binary distribution | |
• Source: | Installing from a source distribution |
Next: Binary, Up: Installation [Contents][Index]
The Expat library and header-files must be installed. Look for the library "libexpat" and the header-file "expat.h".
If this package is to be tested (which is optional), then the CUnit library and header-files must be installed. Look for the library "libcunit" and the header-files "CUnit/CUnit.h" and "CUnit/Basic.h".
If this package is to be built on a Windows system, then the CMake and MinGW packages must be installed. Look for the utility "cmake" and the directory/folder "MinGW".
Next: Source, Previous: Prerequisites, Up: Installation [Contents][Index]
Currently, only an RPM binary distribution is supported.
Download the distribution by browsing to the Unidata UDUNITS-2
at
https://artifacts.unidata.ucar.edu/service/rest/repository/browse/rpm-udunits/udunits/
or by executing, for example, the following commands:
cd ~/Downloads wget https://artifacts.unidata.ucar.edu/repository/rpm-udunits/udunits/udunits-2.2.28-x86_64.rpm
Install the distribution. For example,
sudo rpm --install [--prefix=/opt/udunits] ~/Downloads/udunits-2.2.28-x86_64.rpm
where the argument in square brackets is optional. The default installation
directory is /usr/local
.
Previous: Binary, Up: Installation [Contents][Index]
• Unix: | Building and installing in Unix-like environments | |
• Windows: | Building and installing in Windows environments |
Download the source by browsing to the Unidata UDUNITS-2
at
https://artifacts.unidata.ucar.edu/service/rest/repository/browse/downloads-udunits/
or by executing, for example, the following commands:
cd ~/Downloads curl -O https://artifacts.unidata.ucar.edu/repository/downloads-udunits/udunits-2.2.28.tar.gz
Unpack the distribution in an appropriate place. For example,
cd /opt sudo pax -rz < ~/Downloads/udunits-2.2.28.tar.gz
Build and install the package. For example
cd udunits2-2.2.28 ./configure [--prefix=install_prefix] >&configure.log make all [check] install [install-html] [install-pdf]
where the arguments in square brackets are optional. The default installation prefix is the parent directory of the source directory.
Download the source by browsing to the Unidata UDUNITS-2
at
https://artifacts.unidata.ucar.edu/service/rest/repository/browse/downloads-udunits/
or by executing, for example, the following commands:
cd C:\Users\current_user\Downloads curl -O https://artifacts.unidata.ucar.edu/repository/downloads-udunits/udunits-2.2.28.zip
Unpack the distribution by opening the downloaded file and extracting the contents to, for example, the user’s "Downloads" folder. Note that, by default, the extractor might create an extra top-level folder with a duplicate name. Remove the extra folder from the destination path if this is the case – either before or after extraction.
Build and install the package using cmake(1). For example
cd C:\Users\current_user\Downloads\udunits2-2.2.28 mkdir build cd build cmake [-D CMAKE_INSTALL_PREFIX=install_prefix] .. make all install
where the argument in square brackets is optional. The default installation folder is the parent folder of the source folder.
Next: Utility, Previous: Installation, Up: Top [Contents][Index]
See (udunits2lib)UDUNITS Library, for details on this package’s unit library.
See (udunits2prog)UDUNITS Utility, for details on this package’s unit utility.
The database for the UDUNITS-2
package comprises one XML file containing
unit prefixes and four XML files containing unit definitions:
Next: Complete Index, Previous: Database, Up: Top [Contents][Index]
The home-page for this package can be found at http://www.unidata.ucar.edu/software/udunits/.
Bug reports should be sent to support-udunits@unidata.ucar.edu.
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Copyright 2014 University Corporation for Atmospheric Research and contributors. All rights reserved.
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Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE SOFTWARE.