A common idiom in CMake-based build systems is to have custom commands
that generate files not listed explicitly as outputs so that these
files do not have to be newer than the inputs. The file modification
times of such "byproducts" are updated only when their content changes.
Then other build rules can depend on the byproducts explicitly so that
their dependents rebuild when the content of the original byproducts
really does change.
This "undeclared byproduct" approach is necessary for Makefile, VS, and
Xcode build tools because if a byproduct were listed as an output of a
rule then the rule would always rerun when the input is newer than the
byproduct but the byproduct may never be updated.
Ninja solves this problem by offering a 'restat' feature to check
whether an output was really modified after running a rule and tracking
the fact that it is up to date separately from its timestamp. However,
Ninja also stats all dependencies up front and will only restat files
that are listed as outputs of rules with the 'restat' option enabled.
Therefore an undeclared byproduct that does not exist at the start of
the build will be considered missing and the build will fail even if
other dependencies would cause the byproduct to be available before its
dependents build.
CMake works around this limitation by adding 'phony' build rules for
custom command dependencies in the build tree that do not have any
explicit specification of what produces them. This is not optimal
because it prevents Ninja from reporting an error when an input to a
rule really is missing. A better approach is to allow projects to
explicitly specify the byproducts of their custom commands so that no
phony rules are needed for them. In order to work with the non-Ninja
generators, the byproducts must be known separately from the outputs.
Add a new "BYPRODUCTS" option to the add_custom_command and
add_custom_target commands to specify byproducts explicitly. Teach the
Ninja generator to specify byproducts as outputs of the custom commands.
In the case of POST_BUILD, PRE_LINK, and PRE_BUILD events on targets
that link, the byproducts must be specified as outputs of the link rule
that runs the commands. Activate 'restat' for such rules so that Ninja
knows it needs to check the byproducts, but not for link rules that have
no byproducts.
Use an explicit "$TARGET_FILE" variable instead of "$out" so that
we can have multiple output files while still only referencing the
main one in command lines.
Now that we know the year component of this VS version we
can add it to the generator name. For convenience, map
the name without the year to the name with the year.
Visual Studio 14 (2015) complains if a static character array is
declared with more than 65535 elements. This limit should be large
enough for SharedForward clients, so just hard-code that instead of
trying to compute a limit.
Teach the add_custom_command and add_custom_target commands a new
USES_TERMINAL option. Use it to tell the generator to give the command
direct access to the terminal if possible.
CMake requires both the Desktop SDK and the correct platform SDK
(Windows Phone or Windows Store) to be installed when targeting the
Windows mobile platforms. Verify that the right platform components are
installed and give a more detailed error message when something is
wrong.
Format the reStructuredText markup manually. Organize the command
options into a definition list. Use inline markup to cross-reference
related documents.
string SUBSTRING command now ignores length if it points
past end of string and uses end of string instead.
String SUBSTRING tests now cover more corner cases.
32b91b9e Features: Run GNU feature tests with std=c++14 when available.
82c283f9 Features: Use the correct dialect flag when recording features.
b18155b7 Features: Reorder the GNU C dialect feature tests
e68d5c60 Features: Split the Clang testable features to a separate file.
1abd7cd9 Use containers of labeled search paths instead of individual members
2a9ac4bd Encapsulate search path manipulation functions into a seperate class.
32922840 Refactor and seperate search path construction for find commands
3c497f11 Help: Add notes for topic 'ExternalProject_UPDATE_DISCONNECTED'
aba5cec6 ExternalProject: Add unit tests for UPDATE_DISCONNECTED
3f606fa7 ExternalProject: Add UPDATE_DISCONNECTED option
c0b749cf ExternalProject: Always add a command to a step
The CPackComponentsForAll-*, GeneratorExpression, and
TestsWorkingDirectory tests all build binaries that they later
need to run or package for the tested configuration. Tell the
'ctest --build-and-test' call to use the same configuration
for driving the build process.
Gilles Khouzam
Kitware Robot
Brad King
Rolf Eike Beer
Peter Collingbourne
Dmitry Polyanitsa
Ben Boeckel
Domen Vrankar