ESP32 Forum

Posted: **Thu Jun 04, 2020 10:17 am**

Hello,

I have several components in my project. Some of them are using functions from others.

In order to avoid compiler to strip the functions that are not used by the main component, I use the -u option like this:

main's CMakeLists.txt :

Code: Select all

<snip>

target_link_options(
	${COMPONENT_LIB} 
	PUBLIC
	-u SpiInOut
	)

and this works as expected, no more "undefined reference".

Now, if I want to add several functions, I do something like this :

Code: Select all

target_link_options(
	${COMPONENT_LIB} 
	PUBLIC
	-u SpiInOut 
        -u memcpy1
	)

This does not work because, CMake, generates this command line :

Code: Select all

<snip> -u SpiInOut memcpy1

While it should be

Code: Select all

<snip> -u SpiInOut -u memcpy1

How should I do?

Thanks
Julien

Posted: **Thu Jun 04, 2020 10:45 pm**

Can you try enclosing them in quotes?

Code: Select all

target_link_options(
	${COMPONENT_LIB} 
	PUBLIC
	"-u SpiInOut" "-u memcpy1"
	)

P.S. Note `target_link_options` requires at least a CMake version > 3.13.

Posted: **Mon Jun 08, 2020 1:20 pm**

It doesn't work.

Command line becomes:

Code: Select all

&& /home/ju/tools/crosstool-NG/builds/xtensa-esp32-elf/bin/xtensa-esp32-elf-g++  -mlongcalls -Wno-frame-address  "-u memcpy1" "-u SpiInOut" "-u DelayMs" CMakeFile

as a result : undefined reference to SpiInOut...

Posted: **Tue Jun 09, 2020 12:01 am**

On the contrary, it means that the `-u` argument for `SpiInOut` works, since you're forcing the linker to not drop `SpiInOut` but it is not finding it. Is the source file containing definition for `SpiInOut` is included in the build?

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