Re: [CMake] write file if different?
On 2013-05-28 16:07, Matthew Woehlke wrote:
Is there a built-in way to write a string to a file (a la FILE(WRITE))
that will only write the file if the content would be different? (Or
does FILE(WRITE) already work this way despite no obvious hint in the
documentation that it does?)
Right now I am writing to a temporary file and running cmake -E
copy_if_different, then removing the temporary file, but this seems
inelegant and I am wondering if there is a better solution.
Not strictly built-in, but it looks like the best way is:
set(CMAKE_CONFIGURABLE_FILE_CONTENT ${CONTENT})
configure_file(
${CMAKE_ROOT}/Modules/CMakeConfigurableFile.in
${PATH} @ONLY
)
--
Matthew
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Re: [CMake] write file if different?
You are entitled to your opinion, but there are several system utilities that are available by default on many systems, including rsync. rsync has a well known interface, and is available by default on Linux and Mac OS X. The way CMake does things is often kludgy and just feels wrong. I often write scripts in more effective languages and then run from within CMake on Windows, Linux, and Mac OS X. Perl and Python are often a much better way to go than trying to do everything in CMake. On Wed, May 29, 2013 at 11:14 PM, them...@gmail.com them...@gmail.com wrote: - Reply message - From: j s j.s4...@gmail.com To: Michael Wild them...@gmail.com Cc: CMake mailing list cmake@cmake.org Subject: [CMake] write file if different? Date: Wed, May 29, 2013 20:44 On Wed, May 29, 2013 at 2:32 AM, Michael Wild them...@gmail.com wrote: On 28.05.2013 22:07, Matthew Woehlke wrote: Is there a built-in way to write a string to a file (a la FILE(WRITE)) that will only write the file if the content would be different? (Or does FILE(WRITE) already work this way despite no obvious hint in the documentation that it does?) Right now I am writing to a temporary file and running cmake -E copy_if_different, then removing the temporary file, but this seems inelegant and I am wondering if there is a better solution. You can always use the rsync command, which is available for all systems, including Windows. That's probably the worst possible solution... CMake has everything that iy required to accomplish this built-in, so adding a unnecessary dependency that is only needed by the build system is a really bad idea... -- Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://www.cmake.org/mailman/listinfo/cmake
Re: [CMake] write file if different?
Rsync would be no different than writing the file and using copy_if_different; it would still be two steps, but require additional things to be installed on linux and windows systems. Same with python/perl/bash as appropriate. If you're using those other things you should just use configure so windows people don't attempt to build it with JUST cmake and their favorite compiler installed. On Thu, May 30, 2013 at 9:11 AM, j s j.s4...@gmail.com wrote: You are entitled to your opinion, but there are several system utilities that are available by default on many systems, including rsync. rsync has a well known interface, and is available by default on Linux and Mac OS X. The way CMake does things is often kludgy and just feels wrong. I often write scripts in more effective languages and then run from within CMake on Windows, Linux, and Mac OS X. Perl and Python are often a much better way to go than trying to do everything in CMake. On Wed, May 29, 2013 at 11:14 PM, them...@gmail.com them...@gmail.com wrote: - Reply message - From: j s j.s4...@gmail.com To: Michael Wild them...@gmail.com Cc: CMake mailing list cmake@cmake.org Subject: [CMake] write file if different? Date: Wed, May 29, 2013 20:44 On Wed, May 29, 2013 at 2:32 AM, Michael Wild them...@gmail.com wrote: On 28.05.2013 22:07, Matthew Woehlke wrote: Is there a built-in way to write a string to a file (a la FILE(WRITE)) that will only write the file if the content would be different? (Or does FILE(WRITE) already work this way despite no obvious hint in the documentation that it does?) Right now I am writing to a temporary file and running cmake -E copy_if_different, then removing the temporary file, but this seems inelegant and I am wondering if there is a better solution. You can always use the rsync command, which is available for all systems, including Windows. That's probably the worst possible solution... CMake has everything that iy required to accomplish this built-in, so adding a unnecessary dependency that is only needed by the build system is a really bad idea... -- Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://www.cmake.org/mailman/listinfo/cmake -- Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://www.cmake.org/mailman/listinfo/cmake
Re: [CMake] write file if different?
On 2013-05-30 12:11, j s wrote: On Wed, May 29, 2013 at 11:14 PM, them...@gmail.com wrote: j s wrote: On 28.05.2013 22:07, Matthew Woehlke wrote: Is there a built-in way to write a string to a file (a la FILE(WRITE)) that will only write the file if the content would be different? (Or does FILE(WRITE) already work this way despite no obvious hint in the documentation that it does?) You can always use the rsync command, which is available for all systems, including Windows. That's probably the worst possible solution... CMake has everything that iy required to accomplish this built-in, so adding a unnecessary dependency that is only needed by the build system is a really bad idea... You are entitled to your opinion, but there are several system utilities that are available by default on many systems, including rsync. Really? I have yet to encounter a Windows system that has rsync by default. (For that matter, even on Linux it is not required, and I wouldn't put a lot of faith in finding it on a 'stock' non-Linux/BSD UNIX platform.) Besides, using rsync for a single file where cmake -E copy_if_different (or even configure_file as elsewhere mentioned) is clearly overkill. Not to mention that rsync is not guaranteed to be present even on UNIX systems, much less Windows, whereas CMake is already being used. The way CMake does things is often kludgy and just feels wrong. I often write scripts in more effective languages and then run from within CMake on Windows, Linux, and Mac OS X. Perl and Python are often a much better way to go than trying to do everything in CMake. Sure, and where a) it makes sense and b) I *already require the relevant tools for other reasons*, I do also. But I try to avoid it, because these dependencies are usually NOT present on Windows, especially for end users that want to build from a tarball. (Which is why, when I wrote test discovery for gtest, I did it in pure CMake. It may not be the easiest/cleanest, but I strongly prefer to avoid large external dependencies without much stronger motivation for needing them.) -- Matthew -- Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://www.cmake.org/mailman/listinfo/cmake
Re: [CMake] write file if different?
On Thu, May 30, 2013 at 12:36 PM, Matthew Woehlke matthew.woeh...@kitware.com wrote: On 2013-05-30 12:11, j s wrote: On Wed, May 29, 2013 at 11:14 PM, them...@gmail.com wrote: j s wrote: On 28.05.2013 22:07, Matthew Woehlke wrote: Is there a built-in way to write a string to a file (a la FILE(WRITE)) that will only write the file if the content would be different? (Or does FILE(WRITE) already work this way despite no obvious hint in the documentation that it does?) You can always use the rsync command, which is available for all systems, including Windows. That's probably the worst possible solution... CMake has everything that iy required to accomplish this built-in, so adding a unnecessary dependency that is only needed by the build system is a really bad idea... You are entitled to your opinion, but there are several system utilities that are available by default on many systems, including rsync. Really? I have yet to encounter a Windows system that has rsync by default. (For that matter, even on Linux it is not required, and I wouldn't put a lot of faith in finding it on a 'stock' non-Linux/BSD UNIX platform.) It is available by default on both Mac OS X and Ubuntu Linux, and is readily available as a package on many others. In fact, many package management software require rsync to even run. It is readily available on Windows by installing Cygwin. Besides, using rsync for a single file where cmake -E copy_if_different (or even configure_file as elsewhere mentioned) is clearly overkill. Not to mention that rsync is not guaranteed to be present even on UNIX systems, The original poster's test case may not be the best example for using an external utility. In fact, they'd be better off using something like a custom target having the appropriate dependencies. Barring that they should use a script written in a real scripting language that unambigously performs the steps needed. The way CMake does things is often kludgy and just feels wrong. I often write scripts in more effective languages and then run from within CMake on Windows, Linux, and Mac OS X. Perl and Python are often a much better way to go than trying to do everything in CMake. Sure, and where a) it makes sense and b) I *already require the relevant tools for other reasons*, I do also. But I try to avoid it, because these dependencies are usually NOT present on Windows, especially for end users that want to build from a tarball. (Which is why, when I wrote test discovery for gtest, I did it in pure CMake. It may not be the easiest/cleanest, but I strongly prefer to avoid large external dependencies without much stronger motivation for needing them.) Standard system utilities are the cleanest, and easiest. These tools are readily available on Windows via Cygwin. Most every program I write requires already Boost, Bison, Flex and a Python interpreter, so a Unix like environment is going to be required anyways. I use cmake because it is an accurate Makefile and Visual Studio generator. It's main fault is it's domain specific language. -- Matthew -- Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://www.cmake.org/mailman/listinfo/cmake -- Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://www.cmake.org/mailman/listinfo/cmake
Re: [CMake] write file if different?
On Tue, May 28, 2013 at 1:07 PM, Matthew Woehlke
matthew.woeh...@kitware.com wrote:
Is there a built-in way to write a string to a file (a la FILE(WRITE)) that
will only write the file if the content would be different? (Or does
FILE(WRITE) already work this way despite no obvious hint in the
documentation that it does?)
Right now I am writing to a temporary file and running cmake -E
copy_if_different, then removing the temporary file, but this seems
inelegant and I am wondering if there is a better solution.
I would add a minor note; this seems to be a good way, but you don't
really need to delete the temp file, if you build it in the
${CMAKE_BINARY_DIR}, so it's not laying around in source trees.
It would be nice if such a simple thing didn't require launching a
seperate instance of cmake to do; since it's already in cmake, would
think there would be a way to just 'EXEC( ... )' instead of 'cmake -E
(...)'
--
Matthew
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Re: [CMake] write file if different?
On 2013-05-30 17:24, J Decker wrote:
On Tue, May 28, 2013 at 1:07 PM, Matthew Woehlke
matthew.woeh...@kitware.com wrote:
Is there a built-in way to write a string to a file (a la FILE(WRITE)) that
will only write the file if the content would be different? (Or does
FILE(WRITE) already work this way despite no obvious hint in the
documentation that it does?)
Right now I am writing to a temporary file and running cmake -E
copy_if_different, then removing the temporary file, but this seems
inelegant and I am wondering if there is a better solution.
I would add a minor note; this seems to be a good way, but you don't
really need to delete the temp file, if you build it in the
${CMAKE_BINARY_DIR}, so it's not laying around in source trees.
Sure, but it offends my sense of tidiness to leave it ;-).
It would be nice if such a simple thing didn't require launching a
seperate instance of cmake to do; since it's already in cmake, would
think there would be a way to just 'EXEC( ... )' instead of 'cmake -E
(...)'
As pointed out, configure_file would probably also do the job. What I
was hoping for, however, was a solution where I don't have to much about
with the temporary file myself.
I had two main reasons for posting: to ask if there was an elegant way
to do this that I didn't know about (I haven't heard one), and at some
point ('now', apparently) to inquire if this would be a useful addition
to CMake. A file(WRITE_IF_DIFFERENT) perhaps?
--
Matthew
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Re: [CMake] write file if different?
On 2013-05-29 03:32, Michael Wild wrote: On 28.05.2013 22:07, Matthew Woehlke wrote: Is there a built-in way to write a string to a file (a la FILE(WRITE)) that will only write the file if the content would be different? (Or does FILE(WRITE) already work this way despite no obvious hint in the documentation that it does?) Right now I am writing to a temporary file and running cmake -E copy_if_different, then removing the temporary file, but this seems inelegant and I am wondering if there is a better solution. AFAIK the file is written unconditionally, but you can then use configure_file(... COPYONLY) instead of a round-about execute_process() that calls cmake -E copy_if_different. Actually... no. Well, I could (it would technically work), but because I always write the file, it causes the build rules to always be out of date (i.e. CMake is re-run every time), which is decidedly sub-optimal :-). (Didn't realize that until I finally decided to try it, just now. Although I wonder now if I had actually tried configure_file originally and switched to execute_process for exactly this reason...) So... stronger argument for maybe adding this as an enhancement to CMake. -- Matthew -- Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://www.cmake.org/mailman/listinfo/cmake
Re: [CMake] write file if different?
On Wed, May 29, 2013 at 2:32 AM, Michael Wild them...@gmail.com wrote: On 28.05.2013 22:07, Matthew Woehlke wrote: Is there a built-in way to write a string to a file (a la FILE(WRITE)) that will only write the file if the content would be different? (Or does FILE(WRITE) already work this way despite no obvious hint in the documentation that it does?) Right now I am writing to a temporary file and running cmake -E copy_if_different, then removing the temporary file, but this seems inelegant and I am wondering if there is a better solution. You can always use the rsync command, which is available for all systems, including Windows. AFAIK the file is written unconditionally, but you can then use configure_file(... COPYONLY) instead of a round-about execute_process() that calls cmake -E copy_if_different. Michael -- Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://www.cmake.org/mailman/listinfo/cmake -- Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://www.cmake.org/mailman/listinfo/cmake
Re: [CMake] write file if different?
- Reply message - From: j s j.s4...@gmail.com To: Michael Wild them...@gmail.com Cc: CMake mailing list cmake@cmake.org Subject: [CMake] write file if different? Date: Wed, May 29, 2013 20:44 On Wed, May 29, 2013 at 2:32 AM, Michael Wild them...@gmail.com wrote: On 28.05.2013 22:07, Matthew Woehlke wrote: Is there a built-in way to write a string to a file (a la FILE(WRITE)) that will only write the file if the content would be different? (Or does FILE(WRITE) already work this way despite no obvious hint in the documentation that it does?) Right now I am writing to a temporary file and running cmake -E copy_if_different, then removing the temporary file, but this seems inelegant and I am wondering if there is a better solution. You can always use the rsync command, which is available for all systems, including Windows. That's probably the worst possible solution... CMake has everything that iy required to accomplish this built-in, so adding a unnecessary dependency that is only needed by the build system is a really bad idea...-- Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://www.cmake.org/mailman/listinfo/cmake
[CMake] write file if different?
Is there a built-in way to write a string to a file (a la FILE(WRITE)) that will only write the file if the content would be different? (Or does FILE(WRITE) already work this way despite no obvious hint in the documentation that it does?) Right now I am writing to a temporary file and running cmake -E copy_if_different, then removing the temporary file, but this seems inelegant and I am wondering if there is a better solution. -- Matthew -- Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://www.cmake.org/mailman/listinfo/cmake
