Re: [CMake] CMake and include only libraries
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Hash: SHA1
On 04/05/2011 03:53 AM, Michael Hertling wrote:
CMAKE_MINIMUM_REQUIRED(VERSION 2.8 FATAL_ERROR)
PROJECT(HEADERLIBRARY C)
SET(CMAKE_VERBOSE_MAKEFILE ON)
FILE(WRITE ${CMAKE_BINARY_DIR}/f.h void f(void)\n)
ADD_LIBRARY(f STATIC f.h)
SET_TARGET_PROPERTIES(f PROPERTIES
LINKER_LANGUAGE C PUBLIC_HEADER ${CMAKE_BINARY_DIR}/f.h)
ADD_CUSTOM_COMMAND(TARGET f POST_BUILD
COMMAND ${CMAKE_COMMAND} -E remove $TARGET_FILE:f)
INSTALL(TARGETS f EXPORT f
PUBLIC_HEADER DESTINATION include
ARCHIVE DESTINATION include OPTIONAL)
INSTALL(EXPORT f DESTINATION share)
Note the ARCHIVE DESTINATION *include* to prevent the INSTALL() command
from creating a directory for the non-existing library. The downside of
that approach is a little extra cost to build the empty library each
time make is run.
Nevertheless, the export file created by INSTALL(EXPORT ...) will still
contain a reference to the non-existing libf.a, so I wonder what's the
point of using the INSTALL() command's EXPORT feature with a header-
only library, i.e. what's so bad with INSTALL(FILES ...) or - after
setting up the library's headers - with INSTALL(DIRECTORY ...)?
I tried that, and indeed there remains a reference to the libf.a.
The idea is to have a single uniform mecanism to do export, all the more
that things get more complex when you want to use the built library
either at the build location or at the install location
Since the EXPORT seems to be done for that, I expected it to work with
INSTALL(FILES ...) or INSTALL(DIRECTORY ...) (exactly for headers) but
it does not
Honestly, headers seem sometimes a second class citizen in cmake: there
are some properties related to headers but few header knowledgeable
commands...
On 04/05/2011 03:53 AM, Michael Wild wrote:
I don't see what the problem with install(FILES ...) is? If you have a
header-only library, you just don't need any of the complex EXPORT
stuff. That is only related to the dependencies between libraries,
executables and transitive linking. In the case of a header-only library
you dump the files, create a XXXConfig.cmake and XXXConfigVersion.cmake
file, and be done with.
Well, I tend to disagree. Headers also have dependencies (to other
headers or even to other libraries), so the concepts of transitive
linking are useful as well for header-only libraries.
Again, headers are a full part of software development, so (at least to
me) it makes sense to treat them as well as libraries, executables,...
That they happen to be readble and (usually) machine independent, does
not mean that they do not convey dependencies, have version problems,
... I really think that having a target of type INCLUDES might bring
consistency to cmake, and ease of use to users.
If peope share this view, I might even try to add such a thing.
For now, I guess I have to rely on INSTALL(FILES|DIRECTORY ...)
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Re: [CMake] CMake and include only libraries
On 04/05/2011 11:02 AM, Theodore Papadopoulo wrote:
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
On 04/05/2011 03:53 AM, Michael Hertling wrote:
CMAKE_MINIMUM_REQUIRED(VERSION 2.8 FATAL_ERROR)
PROJECT(HEADERLIBRARY C)
SET(CMAKE_VERBOSE_MAKEFILE ON)
FILE(WRITE ${CMAKE_BINARY_DIR}/f.h void f(void)\n)
ADD_LIBRARY(f STATIC f.h)
SET_TARGET_PROPERTIES(f PROPERTIES
LINKER_LANGUAGE C PUBLIC_HEADER ${CMAKE_BINARY_DIR}/f.h)
ADD_CUSTOM_COMMAND(TARGET f POST_BUILD
COMMAND ${CMAKE_COMMAND} -E remove $TARGET_FILE:f)
INSTALL(TARGETS f EXPORT f
PUBLIC_HEADER DESTINATION include
ARCHIVE DESTINATION include OPTIONAL)
INSTALL(EXPORT f DESTINATION share)
Note the ARCHIVE DESTINATION *include* to prevent the INSTALL() command
from creating a directory for the non-existing library. The downside of
that approach is a little extra cost to build the empty library each
time make is run.
Nevertheless, the export file created by INSTALL(EXPORT ...) will still
contain a reference to the non-existing libf.a, so I wonder what's the
point of using the INSTALL() command's EXPORT feature with a header-
only library, i.e. what's so bad with INSTALL(FILES ...) or - after
setting up the library's headers - with INSTALL(DIRECTORY ...)?
I tried that, and indeed there remains a reference to the libf.a.
The idea is to have a single uniform mecanism to do export, all the more
that things get more complex when you want to use the built library
either at the build location or at the install location
Since the EXPORT seems to be done for that, I expected it to work with
INSTALL(FILES ...) or INSTALL(DIRECTORY ...) (exactly for headers) but
it does not
Honestly, headers seem sometimes a second class citizen in cmake: there
are some properties related to headers but few header knowledgeable
commands...
On 04/05/2011 03:53 AM, Michael Wild wrote:
I don't see what the problem with install(FILES ...) is? If you have a
header-only library, you just don't need any of the complex EXPORT
stuff. That is only related to the dependencies between libraries,
executables and transitive linking. In the case of a header-only library
you dump the files, create a XXXConfig.cmake and XXXConfigVersion.cmake
file, and be done with.
Well, I tend to disagree. Headers also have dependencies (to other
headers or even to other libraries), so the concepts of transitive
linking are useful as well for header-only libraries.
Again, headers are a full part of software development, so (at least to
me) it makes sense to treat them as well as libraries, executables,...
That they happen to be readble and (usually) machine independent, does
not mean that they do not convey dependencies, have version problems,
... I really think that having a target of type INCLUDES might bring
consistency to cmake, and ease of use to users.
If peope share this view, I might even try to add such a thing.
For now, I guess I have to rely on INSTALL(FILES|DIRECTORY ...)
The whole EXPORT stuff is target at ABI compatibility, not API
compatibility. As I said, it is fairly easy to write a fully functional
XXXConfig.cmake.in file for a header-only library. Put something like
the following in it:
# Tell the user project where to find our headers
set(XXX_INCLUDE_DIR @XXX_INCLUDE_DIR@)
# Find required dependency
find_package(YYY REQUIRED)
# Set things up for the user-project
set(XXX_INCLUDE_DIRS ${XXX_INCLUDE_DIR} ${YYY_INCLUDE_DIRS})
set(XXX_LIBRARIES ${YYY_LIBRARIES})
#
I really don't see how CMake could automate this any more, or what
additional information it could generate for you. If your headers have
dependencies, just put the appropriate find_{package,path,library} calls
in there. Besides, you'll have to create a XXXConfig.cmake file anyways
where you would need to include the exported targets, so this is just as
simple.
I'm still a bit wondering what you actually want CMake to do for you.
Michael
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Re: [CMake] CMake and include only libraries
Honestly, headers seem sometimes a second class citizen in cmake: there
are some properties related to headers but few header knowledgeable
commands...
I really don't see how CMake could automate this any more, or what
additional information it could generate for you.
Well, since you asked: it *would* be nice if cmake would know about the
headers needed by a target, or even support header-only targets. Currently
it feels like an artificial divide between shared object files and header
files:
# find required dependency which correctly sets up import targets:
find_package(BAR)
# additional step for headers (with side-effects for other targets)...
include_directories(${BAR_INCLUDE_DIRS})
# ... that is not needed (and in fact discouraged) for libs:
#NO: link_directories(${BAR_LIBRARY_DIRS})
target_link_libraries(foo bar)
To be fair though, most other build-systems are not any better at
handling header files. And since this feature request has already been
discussed in http://public.kitware.com/Bug/view.php?id=115, I'm content
with it only being deferred, not dismissed...
--
Johannes Zarl
Virtual Reality Services
Johannes Kepler University
Informationsmanagement
Altenbergerstrasze 69
4040 Linz, Austria
Phone: +43 732 2468-8321
johannes.z...@jku.at
http://vrc.zid.jku.at
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Re: [CMake] CMake and include only libraries
On 04/04/2011 07:30 PM, Theodore Papadopoulo wrote:
Hi,
I'm trying to use cmake to install a include only library.
I'd like to use the export feature as described in
http://www.itk.org/Wiki/CMake/Tutorials/How_to_create_a_ProjectConfig.cmake_file
and I found the idea of using
set_target_properties(foo PROPERTIES PUBLIC_HEADER
foo.h;${CMAKE_CURRENT_BINARY_DIR}/config.h)
nice. But in my case, I do not have any library to build...
All my attempts to create custom targets or library targets with only
headers fail So I'm left with using install(FILES ...) and forget
this export idea unless someone knows a trick...
Here is a sketch of my CMakelists.txt
SET(Utils_HEADERS ...)
INCLUDE(TestBigEndian)
TEST_BIG_ENDIAN(WORDS_BIGENDIAN)
CONFIGURE_FILE (${CMAKE_CURRENT_SOURCE_DIR}/Utils/config.h.in config.h
@ONLY)
SET(HEADERS)
FOREACH(file ${Utils_HEADERS})
SET(HEADERS ${HEADERS};${CMAKE_CURRENT_SOURCE_DIR}/Utils/${file})
ENDFOREACH()
# Those do not work
#ADD_LIBRARY(UtilsIncludes SHARED ${HEADERS}
${CMAKE_CURRENT_SOURCE_DIR}/Utils/config.h)
#ADD_CUSTOM_TARGET(UtilsIncludes All DEPENDS ${HEADERS}
#${CMAKE_CURRENT_SOURCE_DIR}/Utils/config.h.in)
SET_TARGET_PROPERTIES(UtilsIncludes PROPERTIES
PUBLIC_HEADER
${HEADERS};${CMAKE_CURRENT_BINARY_DIR}/config.h)
INSTALL(TARGETS UtilsIncludes EXPORT UtilsLibraryDepends
LIBRARY DESTINATION lib
PUBLIC_HEADER DESTINATION include/Odyssee++ COMPONENT dev)
Thank's in advance for any hint.
All the best.
Theo.
You might
- build an empty static or shared library from the header files only,
- remove it right after is has been built by a custom command, and
- provide an OPTIONAL clause to the INSTALL() command to prevent
it from failing when it tries to install the library file:
CMAKE_MINIMUM_REQUIRED(VERSION 2.8 FATAL_ERROR)
PROJECT(HEADERLIBRARY C)
SET(CMAKE_VERBOSE_MAKEFILE ON)
FILE(WRITE ${CMAKE_BINARY_DIR}/f.h void f(void)\n)
ADD_LIBRARY(f STATIC f.h)
SET_TARGET_PROPERTIES(f PROPERTIES
LINKER_LANGUAGE C PUBLIC_HEADER ${CMAKE_BINARY_DIR}/f.h)
ADD_CUSTOM_COMMAND(TARGET f POST_BUILD
COMMAND ${CMAKE_COMMAND} -E remove $TARGET_FILE:f)
INSTALL(TARGETS f EXPORT f
PUBLIC_HEADER DESTINATION include
ARCHIVE DESTINATION include OPTIONAL)
INSTALL(EXPORT f DESTINATION share)
Note the ARCHIVE DESTINATION *include* to prevent the INSTALL() command
from creating a directory for the non-existing library. The downside of
that approach is a little extra cost to build the empty library each
time make is run.
Nevertheless, the export file created by INSTALL(EXPORT ...) will still
contain a reference to the non-existing libf.a, so I wonder what's the
point of using the INSTALL() command's EXPORT feature with a header-
only library, i.e. what's so bad with INSTALL(FILES ...) or - after
setting up the library's headers - with INSTALL(DIRECTORY ...)?
Regards,
Michael
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Re: [CMake] CMake and include only libraries
On 04/05/2011 03:53 AM, Michael Hertling wrote:
On 04/04/2011 07:30 PM, Theodore Papadopoulo wrote:
Hi,
I'm trying to use cmake to install a include only library.
I'd like to use the export feature as described in
http://www.itk.org/Wiki/CMake/Tutorials/How_to_create_a_ProjectConfig.cmake_file
and I found the idea of using
set_target_properties(foo PROPERTIES PUBLIC_HEADER
foo.h;${CMAKE_CURRENT_BINARY_DIR}/config.h)
nice. But in my case, I do not have any library to build...
All my attempts to create custom targets or library targets with only
headers fail So I'm left with using install(FILES ...) and forget
this export idea unless someone knows a trick...
Here is a sketch of my CMakelists.txt
SET(Utils_HEADERS ...)
INCLUDE(TestBigEndian)
TEST_BIG_ENDIAN(WORDS_BIGENDIAN)
CONFIGURE_FILE (${CMAKE_CURRENT_SOURCE_DIR}/Utils/config.h.in config.h
@ONLY)
SET(HEADERS)
FOREACH(file ${Utils_HEADERS})
SET(HEADERS ${HEADERS};${CMAKE_CURRENT_SOURCE_DIR}/Utils/${file})
ENDFOREACH()
# Those do not work
#ADD_LIBRARY(UtilsIncludes SHARED ${HEADERS}
${CMAKE_CURRENT_SOURCE_DIR}/Utils/config.h)
#ADD_CUSTOM_TARGET(UtilsIncludes All DEPENDS ${HEADERS}
#${CMAKE_CURRENT_SOURCE_DIR}/Utils/config.h.in)
SET_TARGET_PROPERTIES(UtilsIncludes PROPERTIES
PUBLIC_HEADER
${HEADERS};${CMAKE_CURRENT_BINARY_DIR}/config.h)
INSTALL(TARGETS UtilsIncludes EXPORT UtilsLibraryDepends
LIBRARY DESTINATION lib
PUBLIC_HEADER DESTINATION include/Odyssee++ COMPONENT dev)
Thank's in advance for any hint.
All the best.
Theo.
You might
- build an empty static or shared library from the header files only,
- remove it right after is has been built by a custom command, and
- provide an OPTIONAL clause to the INSTALL() command to prevent
it from failing when it tries to install the library file:
CMAKE_MINIMUM_REQUIRED(VERSION 2.8 FATAL_ERROR)
PROJECT(HEADERLIBRARY C)
SET(CMAKE_VERBOSE_MAKEFILE ON)
FILE(WRITE ${CMAKE_BINARY_DIR}/f.h void f(void)\n)
ADD_LIBRARY(f STATIC f.h)
SET_TARGET_PROPERTIES(f PROPERTIES
LINKER_LANGUAGE C PUBLIC_HEADER ${CMAKE_BINARY_DIR}/f.h)
ADD_CUSTOM_COMMAND(TARGET f POST_BUILD
COMMAND ${CMAKE_COMMAND} -E remove $TARGET_FILE:f)
INSTALL(TARGETS f EXPORT f
PUBLIC_HEADER DESTINATION include
ARCHIVE DESTINATION include OPTIONAL)
INSTALL(EXPORT f DESTINATION share)
Note the ARCHIVE DESTINATION *include* to prevent the INSTALL() command
from creating a directory for the non-existing library. The downside of
that approach is a little extra cost to build the empty library each
time make is run.
Nevertheless, the export file created by INSTALL(EXPORT ...) will still
contain a reference to the non-existing libf.a, so I wonder what's the
point of using the INSTALL() command's EXPORT feature with a header-
only library, i.e. what's so bad with INSTALL(FILES ...) or - after
setting up the library's headers - with INSTALL(DIRECTORY ...)?
Regards,
Michael
I don't see what the problem with install(FILES ...) is? If you have a
header-only library, you just don't need any of the complex EXPORT
stuff. That is only related to the dependencies between libraries,
executables and transitive linking. In the case of a header-only library
you dump the files, create a XXXConfig.cmake and XXXConfigVersion.cmake
file, and be done with.
Michael
Michael
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