Release:1.2 Cmake fails.

[LCWilliams]

Following instructions: made a "build" directory. Cd into it. cmake .., and get greeted by this:

-- IPO / LTO supported, will enable for targets in release build type
You have called ADD_LIBRARY for library curlcpp without any source files. This typically indicates a problem with your CMakeLists.txt file
CMake Error: Could not open file for write in copy operation /curlcppConfig.cmake.tmp
CMake Error: : System Error: Permission denied
CMake Error at CMakeLists.txt:37 (configure_file):
  configure_file Problem configuring file


-- Configuring incomplete, errors occurred!

Running on Linux Mint 19 | Cmake: 3.10.2

Testing release 1.1: and cmake runs fine.

[JosephP91]

@Xeverous hi, any idea of what is happening after last changes?

[Xeverous]

My fault, compare

https://cmake.org/cmake/help/v3.10/command/add_library.html

vs

https://cmake.org/cmake/help/v3.11/command/add_library.html

The minimum version required should be 3.11. Only this and later versions allow a fully source-less target creation and then target_sources calls.

[JosephP91]

@Xeverous Ok, so updating the minimum required cmake version should fix the problem, right?

[Xeverous]

Right.

[JosephP91]

@LCWilliams can you please try now? I have updated the minimum required version from 3.10 to 3.11

[LCWilliams]

@LCWilliams can you please try now? I have updated the minimum required version from 3.10 to 3.11

One moment! :P just crawled out of bed!

[LCWilliams]

Still broken; Updated Cmake to latest (3.17) and still get the error as in OP.
For whatever reason it doesn't appear to like:
configure_file(CMake/curlcppConfig.cmake.in ${CURLCPP_BINARY_DIR}/curlcppConfig.cmake @ONLY)
I'm too unfamiliar with Cmake myself to really go digging at this. D:

[JosephP91]

mmm ok. Are you encountering the same error or is it different? If so, can you post the entire error?

[LCWilliams]

If it helps, when viewing CmakeLists.txt : CURLCPP_BINARY_DIR is the only variable to be blue; all other capitalised variables are green (sytnax highlighting in Xed).

It's the same error. I had just slightly moved the text around when first debugging this hence the 1 line difference I thought meant something. 😛

[JosephP91]

We invoke the Jedi Master of CMake @Xeverous

[LCWilliams]

Ah, I stand corrected: it's the same error: MINUS the problem about using ADD LIBRARY. Sorry, being a derp. For clarification:

lee@LWD004 /tmp/downloads/vivaldi/curlcpp-master/build $ cmake ..
CMake Error: Could not open file for write in copy operation /curlcppConfig.cmake.tmp
CMake Error: : System Error: Permission denied
CMake Error at CMakeLists.txt:8 (configure_file):
  configure_file Problem configuring file


-- IPO / LTO supported, will enable for targets in release build type
-- Configuring incomplete, errors occurred!
See also "/tmp/downloads/vivaldi/curlcpp-master/build/CMakeFiles/CMakeOutput.log".

[LCWilliams]

Okay; no idea what it's potentially done in the backend, but I modified the last command in CmakeLists.txt to this:

configure_file(CMake/curlcppConfig.cmake.in
  ${CMAKE_CURRENT_BINARY_DIR}/curlcppConfig.cmake @ONLY)

and it works~

[Xeverous]

The add library error is gone which is good news, but for:

CMake Error: Could not open file for write in copy operation /curlcppConfig.cmake.tmp
CMake Error: : System Error: Permission denied

it means there are 2 possible issues:

• you actually have no permissions to do this operation
• directory does not exist

Usually it's the latter. The path that CMake outputs is the full path. So /curlcppConfig.cmake.tmp simply means that CURLCPP_BINARY_DIR was empty. I haven't found any presence of this variable so it should be replaced with CMake built-ins. ${CMAKE_CURRENT_BINARY_DIR}/lib/cmake/curlcpp or ${CMAKE_BINARY_DIR}/lib/cmake/curlcpp. Would need to check which one is more correct but any way, all well-known libraries that I use put their cmake config files into CMAKE_INSTALL_PREFIX/lib/cmake/<project_name>.