[CMake] Compiled file cannot be executed

[Swaroop Ramachandra]

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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