[CMake] Compiled file cannot be executed

[Michael Wild]

David is probably right, that you need to add the dependency on  
"generate". However, only add it's target name to both the COMMAND and  
DEPENDS arguments, CMake should figure this out.

Michael

On 27. Aug, 2009, at 21:31, Swaroop Ramachandra wrote:

> Still no luck :( . I really wonder why it is trying to execute my  
> "generate"
> binary even before it is built. Here are my updated lines of code.
> #Trying to compile and run generate.c. generate.c creates a new file
> someoutput.txt and copies all data from someinput.txt to  
> someoutput.txt
> add_executable(generate server/generate.c)
> add_custom_command(
> # I want to generate someoutput.txt
> OUTPUT ${CMAKE_BINARY_DIR}/server/someoutput.txt
> # using the generate program. cmake knows that "generate" refers to  
> the
> above target
> COMMAND generate ${CMAKE_CURRENT_SOURCE_DIR}/server/someinput.txt
> # only run if sominput.txt changed
> DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/server/someinput.txt
> ${CMAKE_BINARY_DIR}/bin/generate${CMAKE_EXECUTABLE_SUFFIX}
> # tell to run in current binary dir
> WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/bin
> # some nice comment in the output
> COMMENT "Generating ${CMAKE_BINARY_DIR}/someoutput.txt"
> VERBATIM
> )
>
>
> 2009/8/27 David Cole <david.cole at kitware.com>
>
>> Use full path file names as DEPENDS arguments.
>> Also: depend on the executable file too so that cmake knows not to  
>> try to
>> run the custom command before the executable is built...
>>
>> i.e. :
>>
>> DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/server/someinput.txt $ 
>> {CMAKE_BINARY_DIR}/bin/generate${CMAKE_EXECUTABLE_SUFFIX}
>>
>>
>> HTH,
>> David
>>
>>
>> On Thu, Aug 27, 2009 at 2:41 PM, Swaroop Ramachandra <swaroopgr at gmail.com
>>> wrote:
>>
>>> Hi Michael,
>>>
>>> Thanks for your reply.  I still have the same problem.
>>> *
>>> *
>>> gmake-3.81[2]: bin/generate: Command not found
>>> lin: gmake-3.81[2]: *** [bin/generate] Error 127
>>> lin: gmake-3.81[1]: *** [CMakeFiles/generate.dir/all] Error 2
>>>
>>>
>>>
>>> Here's my code as is:
>>> #Trying to compile and run generate.c. generate.c creates a new file
>>> someoutput.txt and copies all data from someinput.txt to  
>>> someoutput.txt
>>> add_executable(generate server/generate.c)
>>> add_custom_command(
>>> # I want to generate someoutput.txt
>>> OUTPUT ${CMAKE_BINARY_DIR}/server/someoutput.txt
>>> # using the generate program. cmake knows that "generate" refers  
>>> to the
>>> above target
>>> COMMAND generate ${CMAKE_CURRENT_SOURCE_DIR}/server/someinput.txt
>>> # only run if sominput.txt changed
>>> DEPENDS server/someinput.txt
>>> # tell to run in current binary dir
>>> WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/bin
>>> # some nice comment in the output
>>> COMMENT "Generating ${CMAKE_BINARY_DIR}/someoutput.txt"
>>> VERBATIM
>>> )
>>>
>>>
>>> Still the same issue. I guess it is trying to execute my  
>>> "generate" even
>>> before it is compiled. Does CMake see that in the line "COMMAND"  
>>> generate
>>> refers to the compiled one? Again, since generate is created in  
>>> round one of
>>> make, the second run sees the "generate" and runs fine.
>>>
>>> Any help is greatly appreciated! Thanks for your time!
>>>
>>> Regards,
>>> Swaroop
>>>
>>> 2009/8/27 Michael Wild <themiwi at gmail.com>
>>>
>>>
>>>> On 27. Aug, 2009, at 0:58, Swaroop Ramachandra wrote:
>>>>
>>>> Hi,
>>>>>
>>>>> I'm trying to do the following in my CMake file:
>>>>>
>>>>> 1. Generate a "xyz.txt" file
>>>>> 2. Compile a "generate.c" file to give out a  "generate" binary  
>>>>> in my
>>>>> bin
>>>>> directory.
>>>>> 3. Execute the "generate" binary (The binary just reads contents  
>>>>> of
>>>>> "xyz.txt" and creates a copy of "xyz.txt"using read() and write()
>>>>> functions
>>>>> in C)
>>>>>
>>>>> The problem:
>>>>> When I do a fresh build, 1 and 2 succeed. 3 fails with the  
>>>>> following
>>>>> error
>>>>> *"bin/generate: Command not found"*
>>>>>
>>>>> However, if I *re-run the build immediately* after, since the  
>>>>> "generate"
>>>>> binary is already created, all 3 successfully execute. Here's a  
>>>>> snippet
>>>>> of
>>>>> what I have written.
>>>>>
>>>>> ------------
>>>>> ------------
>>>>> /*---- Code to generate xyz.txt -- Successfully generated each
>>>>> time------*/
>>>>> ----------
>>>>> ---------
>>>>> ADD_EXECUTABLE(generate ${CMAKE_CURRENT_SOURCE_DIR}/server/ 
>>>>> generate.c)
>>>>>
>>>>> set(GEN ${CMAKE_BINARY_DIR}/bin/generate)
>>>>>
>>>>> ADD_CUSTOM_COMMAND(
>>>>> TARGET generate POST_BUILD
>>>>> COMMAND ${GEN}
>>>>> DEPENDS ${CMAKE_BINARY_DIR}/server/xyz.txt}
>>>>> )
>>>>> In my ADD_CUSTOM_COMMAND, I have specified POST_BUILD, which I
>>>>> understood to
>>>>> be that the command will be executed only after creation of the
>>>>> "generate"
>>>>> binary.
>>>>>
>>>>
>>>> That's the wrong way to go about it. the TARGET form of the
>>>> add_custom_command is intended to "finish" the actual target.  
>>>> What you want
>>>> is something like this:
>>>>
>>>> # no need for absolute paths...
>>>> add_executable(generate server/generate.c)
>>>>
>>>> add_custom_command(
>>>> # tell cmake you want to generate xyz.c
>>>> OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/xyz.c
>>>> # using the generate program. cmake knows that "generate" refers  
>>>> to the
>>>> above target
>>>> COMMAND generate ${CMAKE_CURRENT_SOURCE_DIR}/xyz.txt
>>>> # only run if xyz.txt changed
>>>> DEPENDS xyz.txt
>>>> # tell to run in current binary dir
>>>> WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
>>>> # some nice comment in the output
>>>> COMMENT "Generating ${CMAKE_CURRENT_BINARY_DIR}/xyz.c"
>>>> VERBATIM
>>>> )
>>>>
>>>>
>>>> And then you simply use ${CMAKE_CURRENT_BINARY_DIR}/xyz.c in one  
>>>> of your
>>>> other targets. CMake will then know that it first needs to create  
>>>> target
>>>> "generate", then run the program on xyz.txt to create
>>>> ${CMAKE_CURRENT_BINARY_DIR}/xyz.c, and finally use that to build  
>>>> the actual
>>>> target.
>>>>
>>>>
>>>> HTH
>>>>
>>>> Michael
>>>>
>>>>
>>>
>>>
>>> --
>>>
>>> Samuel Goldwyn<http://www.brainyquote.com/quotes/authors/s/samuel_goldwyn.html 
>>> > - "I'm willing to admit that I may not always be right, but I am  
>>> never
>>> wrong."
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>>
>>
>
>
> -- 
>
> Ted Turner <http://www.brainyquote.com/quotes/authors/t/ted_turner.html 
> >  -
> "Sports is like a war without the killing."