Specify the output directory
-v Print version number and license info
-help Print this message
ignored
```
### NO OK? This is an error in the generated batch file because call to cmd file is not used!
Q: Any idea how this can be solved a portable way?
Q: What is the **MAX** command length, after that, a batch file is generated?
Q: Is this a `windows` specifically problem or a general `ninja generator` problem?
---
### Author:  [@ben.boeckel](https://discourse.cmake.org/u/ben.boeckel)
#### Post date: [October 26, 2021, 8:54pm UTC](https://discourse.cmake.org/t/add-custom-command-does-not-work-in-each-cases-but-there-is-no-error/4338/2 "2021-10-26T20:54:41Z")
> [@ClausKlein](#):
>
> Any idea how this can be solved a portable way?
Write a CMake script that does `execute_process` on its own (configured with the paths you need passed in as `-D` or via `configure_file`) and then call it with `cmake -P …`.
> [@ClausKlein](#):
>
> What is the **MAX** command length, after that, a batch file is generated?
Platform dependent.
> [@ClausKlein](#):
>
> Is this a `windows` specifically problem or a general `ninja generator` problem?
How each generator deals with over-long command lines is probably unique. `make` generators have a line per command while `ninja` will do `cmd1 && cmd2` (or other ways of concatenating them, I don’t remember off hand), so `make` won’t hit the limit so easily.
---
### Author:  [@ClausKlein](https://discourse.cmake.org/u/ClausKlein)
#### Post date: [October 26, 2021, 9:26pm UTC](https://discourse.cmake.org/t/add-custom-command-does-not-work-in-each-cases-but-there-is-no-error/4338/3 "2021-10-26T21:26:40Z")
I can use
> [@ClausKlein](#):
>
> `call ${IDL_COMPILER} -Ipath1 -I... -IpathN ...`
on **windows** , than it works. But this is **NOT** portable!
My problem was the changed behaviour as I needed to add more include path arguments.
The next commend was not longer executed and I saw not why?
---
### Author:  [@ben.boeckel](https://discourse.cmake.org/u/ben.boeckel)
#### Post date: [October 26, 2021, 10:26pm UTC](https://discourse.cmake.org/t/add-custom-command-does-not-work-in-each-cases-but-there-is-no-error/4338/4 "2021-10-26T22:26:18Z")
Why do you need `call`? What does the compiler do that is modifying the parent process environment? If it is a `bat` script itself, the command should itself be `cmd;path/to/idlc.bat`, no (just like a Python script would be `${Python_EXECUTABLE};path/to/idlc.py`)? Sure, non-Windows support shebang lines for such things, but Windows has mechanisms for that too AFAIK.
> [@ClausKlein](#):
>
> My problem was the changed behaviour as I needed to add more include path arguments.
> The next commend was not longer executed and I saw not why?
What changed behavior? CMake? If so, what version worked and what version is not working anymore? If there are any versions in between, knowing which version started to break things would be useful in tracking down this change. Additionally, can you provide a small self-contained example that demonstrates the problem so that we can test it and fix it?
---
### Author:  [@ClausKlein](https://discourse.cmake.org/u/ClausKlein)
#### Post date: [October 27, 2021, 4:59am UTC](https://discourse.cmake.org/t/add-custom-command-does-not-work-in-each-cases-but-there-is-no-error/4338/5 "2021-10-27T04:59:19Z")
> [@ben.boeckel](#):
>
> Why do you need `call`?
The ninja rule is something like this:
```batch
cmd /c path/to/cmake/generated.bat
```
But the batch file need to use:
`call idl2cpp.cmd && do some post processing`
> [@ben.boeckel](#):
>
> What changed behavior?
It is not changed with `CMake version`. It was changed by me!
My project in development and on **Windows** , you needs much more `path` entries and `include_directories` then on other build host OS environments. 🥴
> [@ben.boeckel](#):
>
> Additionally, can you provide a small self-contained example that demonstrates the problem so that we can test it and fix it?
sure, see
>
---
### Author:  [@ben.boeckel](https://discourse.cmake.org/u/ben.boeckel)
#### Post date: [October 27, 2021, 2:40pm UTC](https://discourse.cmake.org/t/add-custom-command-does-not-work-in-each-cases-but-there-is-no-error/4338/6 "2021-10-27T14:40:05Z")
> [@ClausKlein](#):
>
> The ninja rule is something like this:
>
> ```auto
> cmd /c path/to/cmake/generated.bat
>
> ```
>
> But the batch file need to use:
>
> `call idl2cpp.cmd && do some post processing`
I would just write my own batch script and have CMake use `cmd /c` on that. CMake has no idea that your tool uses `cmd` and requires `call` (and there’s no way to tell it to do so because there’s no guarantee that `cmd` is even used by the build tool; `nmake` just calls `CreateProcess` AFAIK).
> [@ClausKlein](#):
>
> My project in development and on **Windows** , you needs much more `path` entries and `include_directories` then on other build host OS environments.
Ah, yep 🙂 . Welcome to cross platform development 🙂 .