Failed to build examples/ffi/ffi-host on ESP32

[stc1988]

Build environment: macOS
Moddable SDK version: 8.1.1
Target device: Moddable Six

Steps to Reproduce

1. Build and install the examples/ffi/ffi-host app using this build command: mcconfig -d -m -p esp32/moddable_six
2. See error

/Users/satoshi/.espressif/tools/xtensa-esp-elf/esp-15.2.0_20251204/xtensa-esp-elf/bin/../lib/gcc/xtensa-esp-elf/15.2.0/../../../../xtensa-esp-elf/bin/ld: xs_esp32s3.a(mc.xs.c.o):/Users/satoshi/Projects/moddable/build/tmp/esp32/moddable_six/debug/ffi-host/mc.xs.c:760:(.rodata.gxBuilders10+0x0): undefined reference to `FFI_destructor'
/Users/satoshi/.espressif/tools/xtensa-esp-elf/esp-15.2.0_20251204/xtensa-esp-elf/bin/../lib/gcc/xtensa-esp-elf/15.2.0/../../../../xtensa-esp-elf/bin/ld: xs_esp32s3.a(mc.xs.c.o):(.rodata.gxBuilders10+0xc): undefined reference to `FFI_constructor'
/Users/satoshi/.espressif/tools/xtensa-esp-elf/esp-15.2.0_20251204/xtensa-esp-elf/bin/../lib/gcc/xtensa-esp-elf/15.2.0/../../../../xtensa-esp-elf/bin/ld: xs_esp32s3.a(mc.xs.c.o):(.rodata.gxHeap+0xd408): undefined reference to `FFI_constructor'
/Users/satoshi/.espressif/tools/xtensa-esp-elf/esp-15.2.0_20251204/xtensa-esp-elf/bin/../lib/gcc/xtensa-esp-elf/15.2.0/../../../../xtensa-esp-elf/bin/ld: xs_esp32s3.a(mc.xs.c.o):(.rodata.gxHeap+0xd96c): undefined reference to `FFI_destructor'
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.
ninja failed with exit code 1, output of the command is in the /Users/satoshi/Projects/moddable/build/tmp/esp32/moddable_six/debug/ffi-host/xsProj-esp32s3/build/log/idf_py_stderr_output_14265 and /Users/satoshi/Projects/moddable/build/tmp/esp32/moddable_six/debug/ffi-host/xsProj-esp32s3/build/log/idf_py_stdout_output_14265
make: *** [build] Error 1

[phoddie]

Note that this works in the simulator.

[phoddie]

The ffi-host app can only work on hosts that support dynamic native libraries. The ESP32 does not. We'll add the following text to the FFI documentation:

Note: This application loads the FFI code from a shared library/DLL. It is currently only supported on desktop simulator builds, as most microcontrollers do not support runtime loading and linking of shared libraries.

[stc1988]

Thanks for confirming. I understand the cause, so I’ll close this issue once the documentation is updated.