ESP32 Forum

Posted: **Mon Mar 04, 2019 10:26 am**

I need to generate header files at compile time. As https://docs.espressif.com/projects/esp ... onentbuild claims it can be done using Makefile.componentbuild file. However there are no examples and I can not find any in the web.

I have tried to use additional component for that which overrides build and clean targets and sets COMPONENT_ADD_LDFLAGS to empty string. Unfortunately ESP-IDF build system still tries to do something with component's library which is not created in the case of pure code generating component.

As a last resort I can think of a custom target which will be executed before building sources. I don't want to create explicit dependencies for sources on this code generation target since there are quite a lot of files which include generated header and it is tedious to manage these deps manually. Therefore I would like to have this target always built before build target is executed but I don't really know how to do that.

I am talking about Make build system.

Thanks!

Posted: **Mon Mar 04, 2019 3:29 pm**

Hi nameofuser1,

Please follow the description in the docs https://docs.espressif.com/projects/esp ... generation, you can see some usage examples here https://github.com/espressif/esp-idf/bl ... ent.mk#L65.

If you don't want to define dependencies, it's possible to setup the target as PHONY, so at the end your component.mk might look something like:

Code: Select all

COMPONENT_EXTRA_CLEAN := generated_file

$(COMPONENT_LIBRARY): generated_file

.PHONY: generated_file

generated_file:
	echo "Generating file" > $(COMPONENT_PATH)/generated_file

Since you're talking about GNU Make build system, so please take it only as a side-note (or a note to other users) that using CMake, generating of source files is described here https://docs.espressif.com/projects/esp ... generation,

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