#pragma once is a widely supported compiler pragma, even though it is
not part of the C++ standard. Many of the issues keeping #pragma once
from being standardized (distributed filesystems, build farms, hard
links, etc.) do not apply to CMake - it is easy to build CMake on a
single machine. CMake also does not install any header files which can
be consumed by other projects (though cmCPluginAPI.h has been
deliberately omitted from this conversion in case anyone is still using
it.) Finally, #pragma once has been required to build CMake since at
least August 2017 (7f29bbe6 enabled server mode unconditionally, which
had been using #pragma once since September 2016 (b13d3e0d)). The fact
that we now require C++11 filters out old compilers, and it is unlikely
that there is a compiler which supports C++11 but does not support
#pragma once.

Ref: #19499

We now require C++11 support including `override`.  Drop use of
the old compatibility macro.  Convert references as follows:

    git grep -l CM_OVERRIDE -- '*.h' '*.hxx' '*.cxx' |
      xargs sed -i 's/CM_OVERRIDE/override/g'

Also remove `#include "cmConfigure.h"` from most source files.

Automate with:

git grep -l '#include <cm_' -- Source \
  | xargs sed -i 's/#include <\(cm_.*\)>/#include "\1"/g'

git grep -l '#include <cmsys/' -- Source \
  | xargs sed -i 's/#include <\(cmsys\/.*\)>/#include "\1"/g'

git grep -l '#include <cm[A-Z]' -- Source \
  | xargs sed -i 's/#include <\(cm[A-Z].*\)>/#include "\1"/g'

Make sure that `#include <cmConfigure.h>` is followed by an empty line
in header files.  This is necessary to make sure that changing <> to ""
does not affect the include ordering of clang-format.

Automate with:

git grep -l '#include <cmConfigure.h>' | grep -v '.cxx$' \
| xargs sed -i '/#include <cmConfigure.h>/ { N; N; s/\n\{1,2\}/\n\n/ }'

Per-source copyright/license notice headers that spell out copyright holder
names and years are hard to maintain and often out-of-date or plain wrong.
Precise contributor information is already maintained automatically by the
version control tool.  Ultimately it is the receiver of a file who is
responsible for determining its licensing status, and per-source notices are
merely a convenience.  Therefore it is simpler and more accurate for
each source to have a generic notice of the license name and references to
more detailed information on copyright holders and full license terms.

Our `Copyright.txt` file now contains a list of Contributors whose names
appeared source-level copyright notices.  It also references version control
history for more precise information.  Therefore we no longer need to spell
out the list of Contributors in each source file notice.

Replace CMake per-source copyright/license notice headers with a short
description of the license and links to `Copyright.txt` and online information
available from "https://cmake.org/licensing".  The online URL also handles
cases of modules being copied out of our source into other projects, so we
can drop our notices about replacing links with full license text.

Run the `Utilities/Scripts/filter-notices.bash` script to perform the majority
of the replacements mechanically.  Manually fix up shebang lines and trailing
newlines in a few files.  Manually update the notices in a few files that the
script does not handle.

Kitware Robot authored 8 years ago and Brad King committed 8 years ago

Run the `Utilities/Scripts/clang-format.bash` script to update
all our C++ code to a new style defined by `.clang-format`.
Use `clang-format` version 3.8.

* If you reached this commit for a line in `git blame`, re-run the blame
  operation starting at the parent of this commit to see older history
  for the content.

* See the parent commit for instructions to rebase a change across this
  style transition commit.

Drop all GetTerseDocumentation and GetFullDocumentation methods from
commands.  The command documentation is now in Help/command/*.rst files.

Sean McBride authored 11 years ago and Brad King committed 11 years ago

A doxygen \brief is ended with a newline, so remove a newline right
after \brief to fix clang -Wdocumentation warning.

Alexander Neundorf authored 12 years ago and Brad King committed 12 years ago

The code handling IMPLICIT_DEPENDS was only able to track a single file,
the latest file replaced earlier files in the list.

The documentation now mentions that the language has to be prefixed to
every file and the test now uses two implicit dependencies, where only
the second is modified to trigger re-running of the custom command.

Alex

Inspired-by: Michael Wild <themiwi@users.sourceforge.net>

Kitware Robot authored 12 years ago and Brad King committed 12 years ago

Our Git commit hooks disallow modification or addition of lines with
trailing whitespace.  Wipe out all remnants of trailing whitespace
everywhere except third-party code.

Run the following shell code:

git ls-files -z -- \
 bootstrap doxygen.config '*.readme' \
 '*.c' '*.cmake' '*.cpp' '*.cxx' \
 '*.el' '*.f' '*.f90' '*.h' '*.in' '*.in.l' '*.java' \
 '*.mm' '*.pike' '*.py' '*.txt' '*.vim' |
egrep -z -v '^(Utilities/cm|Source/(kwsys|CursesDialog/form)/)' |
egrep -z -v '^(Modules/CPack\..*\.in)' |
xargs -0 sed -i 's/ \+$//'

Yury G. Kudryashov authored 13 years ago and Brad King committed 13 years ago

Use const_cast for the special case in cmFindBase where
GetFullDocumentation calls GenerateDocumentation.

A common mistake when using custom commands is to list the output of a
command in multiple targets that may build in parallel.  Warn against
this case in the documentation and suggest a better approach.

This also fixes handling of trailing slashes in the directory name.

Evaluate in the COMMAND arguments of custom commands the generator
expression syntax introduced in commit d2e1f2b4 (Introduce "generator
expressions" to add_test, 2009-08-11).  These expressions have a syntax
like $<TARGET_FILE:mytarget> and are evaluated during build system
generation.  This syntax allows per-configuration target output files to
be referenced in custom command lines.

The behavior of add_custom_command when no DEPENDS option is specified
matches that of standard Make behavior, but it does not hurt to describe
it explicitly.

This converts the CMake license to a pure 3-clause OSI-approved BSD
License.  We drop the previous license clause requiring modified
versions to be plainly marked.  We also update the CMake copyright to
cover the full development time range.

The previous wording of the VERBATIM option documentation in the
add_custom_command and add_custom_target commands was confusing.  It
could be interpreted as the opposite of what the option means (no
escaping instead of escaping).  This clarifies the documentation to
explicitly state that it escapes.

This explicitly states the scope of add_custom_command rules in
the documentation of add_custom_command and add_custom_target.
See issue #8815.

  - Option was recently added but never released.
  - Custom commands no longer depend on build.make so we do
    not need the option.
  - Rule hashes now take care of rebuilding when rules change
    so the dependency is not needed.

  - Allows make rules to be created with no dependencies.
  - Such rules will not re-run even if the commands themselves change.
  - Useful to create rules that run only if the output is missing.

ENH: Make add_custom_command interpret relative OUTPUT locations with respect to the build tre instead of the source tree.  This can greatly simplify user code since generating a file will not need to reference CMAKE_CURRENT_BINARY_DIR.  The new behavior is what users expect 99% of the time.

ENH: add return and break support to cmake, also change basic command invocation signature to be able to return extra informaiton via the cmExecutionStatus class

ENH: Added IMPLICIT_DEPENDS option to ADD_CUSTOM_COMMAND.  It currently works only for Makefile generators.  It allows a custom command to have implicit dependencies in the form of C or CXX sources.

BUG: Target names in the COMMAND part of a custom command should not create a file-level dependency that forces the command to rerun when the executable target rebuilds, but the target-level dependency should still be created.  Target names in a DEPENDS should do both a target-level and file-level dependency.  Updated the BuildDepends test to check that this works.

ENH: Added APPEND option to ADD_CUSTOM_COMMAND to allow extra dependencies to be connected later.  This is useful to create one rule and then have a macro add things to it later.  This addresses bug#2151.

ENH: Added SYMBOLIC source file property to mark custom command outputs that are never actually created on disk.  This is used by the Watcom WMake generator to generate the .SYMBOLIC mark on the files in the make system.

ENH: Added VERBATIM option to ADD_CUSTOM_COMMAND and ADD_CUSTOM_TARGET commands.  This option enables full escaping of custom command arguments on all platforms.  See bug#3786.