Currently the implementation macro for `check_symbol_exists` is
`_check_symbol_exists`, which impedes CMake users from overriding the
`check_symbol_exists` macro themselves.
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names and years are hard to maintain and often out-of-date or plain wrong.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.
The cleanup in commit 4f2fcce4 (Check*: Allow result variables to
contain regex special characters, 2014-07-31) broke old VXL code that
abuses the old "if(MATCHES)" implementation by using
SET( ${VARIABLE} ${VARIABLE} )
to reset a check result variable. Add a compatibility hack to the
CheckFunctionExists, CheckIncludeFileCXX, and CheckSymbolExists modules
to re-run their checks when the result variable is set to its own name.
Use STREQUAL instead of MATCHES so that special characters still work.
Prior to the existence of the if(DEFINED) condition, many of our Check
modules implemented the condition with a hack that takes advantage of
the auto-dereference behavior of the if() command to detect if a
variable is defined. The hack has the form:
if("${VAR} MATCHES "^${VAR}$")
where "${VAR}" is a macro argument reference. However, this does not
work when the variable named in the macro argument contains characters
that have special meaning in regular expressions, such as '+'. Run the
command
git grep -E 'if\("\$\{.*\}" MATCHES "\^\$\{.*\}\$"\)' -- Modules/Check*
to identify lines with this problem. Use if(NOT DEFINED) instead.
Since commit 7d47c693 (Drop compatibility with CMake < 2.4, 2013-10-08)
we no longer need to use the configure_file IMMEDIATE option to support
compatibility modes less than 2.0.
Imported targets are re-exported so that they can be used by the
try_compile generated code with target_link_libraries.
This makes the use of the cmake_expand_imported_targets macro
obsolete. The macro is not able to expand the generator expressions
which may appear in the IMPORTED_LINK_INTERFACE_LIBRARIES content.
Instead it just sees them as 'not a target'.
Ancient versions of CMake required else(), endif(), and similar block
termination commands to have arguments matching the command starting the
block. This is no longer the preferred style.
Run the following shell code:
for c in else endif endforeach endfunction endmacro endwhile; do
echo 's/\b'"$c"'\(\s*\)(.\+)/'"$c"'\1()/'
done >convert.sed &&
git ls-files -z -- bootstrap '*.cmake' '*.cmake.in' '*CMakeLists.txt' |
egrep -z -v '^(Utilities/cm|Source/kwsys/)' |
egrep -z -v 'Tests/CMakeTests/While-Endwhile-' |
xargs -0 sed -i -f convert.sed &&
rm convert.sed
Add the function cmake_expand_imported_targets() to expand imported
targets in a list of libraries into their on-disk file names for a
particular configuration. Adapt the implementation from KDE's
HANDLE_IMPORTED_TARGETS_IN_CMAKE_REQUIRED_LIBRARIES which has been in
use for over 2 years. Call the function from all the Check*.cmake
macros to handle imported targets named in CMAKE_REQUIRED_LIBRARIES.
Alex
Otherwise the compiler may optimize out the reference to the symbol as the
previous version was not really using this. This leads to symbols that are
only in a header but not in the given libraries to be reported as present.
This came up on the first try to fix bug 11333 as "gcc -O3" would optimize
out the reference to pthread_create() so the correct library the symbol is in
was not detected.
The new test code was suggested by Brad King.
The test "complex" sets the variable CMAKE_BACKWARDS_COMPATIBILITY
to 1.4. When that variable is set, configure_file does not default
to IMMEDIATE mode processing. And so, the output file likely does
not exist yet by the time the next line in the CMakeLists.txt file
is processed. When that next line is "try_compile" on that file,
this is a problem.
Fix the problem by explicitly using IMMEDIATE in the configure_file
call.
This problem was quite mysterious, as it only showed up on the
"complex" test, when the previous commit introduced a CheckSymbolExists
call into the FindThreads module. Which is not even explicitly included
in the "complex" test... FindThreads gets included indirectly only
as a side effect of setting CMAKE_BACKWARDS_COMPATIBILITY to 1.4 and
even then it's included indirectly by auto-inclusion of
CMakeBackwardCompatibilityC.cmake...
Wow. Just wow.
The check works for macros, functions, and variables, but not for types
or enumeration values. Clearly describe the behavior of the check with
respect to each symbol type.
This adds copyright/license notification blocks CMake's non-find
modules. Most of the modules had no notices at all. Some had notices
referring to the BSD license already. This commit normalizes existing
notices and adds missing notices.
For example:
CHECK_HEADER_EXISTS("type.h" HAVE_TYPE_H)
is:
CHECK_SYMBOL_EXISTS(main "type.h" HAVE_TYPE_H)
CHECK_LIBRARY_EXISTS("nsl" gethostname HAVE_LIBNSL)
would be
SET(CMAKE_REQUIRED_LIBRARIES "nsl")
CHECK_SYMBOL_EXISTS(gethostname "netdb.h" HAVE_LIBNSL)
...
