Hi there,
platformio is really giving me a hard time lately, due to problems and bugs yesterday I did a clean reinstall of platformio. Building was no problem after that.
Today I start Visual Studio again and I get this when compiling:
c:/users/theuser/.platformio/packages/toolchain-xtensa-esp32/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: .pio\build\esp32-2432S024C\libFrameworkArduino.a(main.cpp.o):(.literal._Z8loopTaskPv+0x8): undefined reference to `setup()'
c:/users/theuser/.platformio/packages/toolchain-xtensa-esp32/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: .pio\build\esp32-2432S024C\libFrameworkArduino.a(main.cpp.o):(.literal._Z8loopTaskPv+0xc): undefined reference to `loop()'
c:/users/theuser/.platformio/packages/toolchain-xtensa-esp32/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: .pio\build\esp32-2432S024C\libFrameworkArduino.a(main.cpp.o): in function `loopTask(void*)':
C:/Users/theuser/.platformio/packages/framework-arduinoespressif32/cores/esp32/main.cpp:42: undefined reference to `setup()'
c:/users/theuser/.platformio/packages/toolchain-xtensa-esp32/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: C:/Users/theuser/.platformio/packages/framework-arduinoespressif32/cores/esp32/main.cpp:48: undefined reference to `loop()'
collect2.exe: error: ld returned 1 exit status
*** [.pio\build\esp32-2432S024C\firmware.elf] Error 1
Even if I didn’t change the code since yesterday I thought there might be some error so I reduced it to:
void setup() { }
void loop() { }
Same problem, also tried clearing the .pio directory.
What is wrong ? 
thanks
What’s the content of your platformio.ini and what the name and location of your source-file?
It should be something like src/main.cpp
yes:
src/main.cpp
ini:
; PlatformIO Project Configuration File
;
; Build options: build flags, source filter
; Upload options: custom upload port, speed and extra flags
; Library options: dependencies, extra library storages
; Advanced options: extra scripting
;
; Please visit documentation for the other options and examples
; https://docs.platformio.org/page/projectconf.html
[platformio]
#default_envs = esp32-1732S019C
#default_envs = esp32-1732S019N
#default_envs = esp32-2424S012C
#default_envs = esp32-2424S012N
default_envs = esp32-2432S024C
#default_envs = esp32-2432S024N
#default_envs = esp32-2432S024R
#default_envs = esp32-2432S028R
#default_envs = esp32-2432S028Rv2
#default_envs = esp32-2432S032C
#default_envs = esp32-2432S032N
#default_envs = esp32-2432S032R
#default_envs = esp32-3248S035C
#default_envs = esp32-3248S035R
#default_envs = esp32-4827S043C
#default_envs = esp32-4827S043N
#default_envs = esp32-4827S043R
#default_envs = esp32-4848S040C
#default_envs = esp32-8048S043C
#default_envs = esp32-8048S043N
#default_envs = esp32-8048S043R
#default_envs = esp32-8048S050C
#default_envs = esp32-8048S050N
#default_envs = esp32-8048S050R
#default_envs = esp32-8048S070C
#default_envs = esp32-8048S070N
[env]
platform = espressif32
framework = arduino
monitor_speed = 115200
#monitor_speed = 9600
monitor_rts = 0
monitor_dtr = 0
monitor_filters = esp32_exception_decoder , send_on_enter
# Partition scheme for OTA
board_build.partitions = min_spiffs.csv
build_flags =
-Ofast
#-Wall
-DCORE_DEBUG_LEVEL=ARDUHAL_LOG_LEVEL_VERBOSE
# LVGL settings
-DLV_CONF_PATH=${PROJECT_INCLUDE_DIR}/lv_conf.h
#lib_deps = rzeldent/esp32_smartdisplay
lib_deps =
https://github.com/rzeldent/esp32-smartdisplay.git
https://github.com/schreibfaul1/ESP32-audioI2S
[env:esp32-1732S019C]
board = esp32-1732S019C
[env:esp32-1732S019N]
board = esp32-1732S019N
[env:esp32-2424S012C]
board = esp32-2424S012C
[env:esp32-2424S012N]
board = esp32-2424S012N
[env:esp32-2432S024C]
board = esp32-2432S024C
[env:esp32-2432S024N]
board = esp32-2432S024N
[env:esp32-2432S024R]
board = esp32-2432S024R
[env:esp32-2432S028R]
board = esp32-2432S028R
# Commented out because define creates an error during CI
#[env:esp32-2432S028Rv2]
#board = esp32-2432S028Rv2
[env:esp32-2432S032C]
board = esp32-2432S032C
[env:esp32-2432S032N]
board = esp32-2432S032N
[env:esp32-2432S032R]
board = esp32-2432S032R
[env:esp32-3248S035C]
board = esp32-3248S035C
[env:esp32-3248S035R]
board = esp32-3248S035R
[env:esp32-4827S043C]
board = esp32-4827S043C
[env:esp32-4827S043N]
board = esp32-4827S043N
[env:esp32-4827S043R]
board = esp32-4827S043R
[env:esp32-4848S040C]
board = esp32-8048S043C
[env:esp32-8048S043C]
board = esp32-8048S043C
[env:esp32-8048S043N]
board = esp32-8048S043N
[env:esp32-8048S043R]
board = esp32-8048S043R
[env:esp32-8048S050C]
board = esp32-8048S050C
[env:esp32-8048S050N]
board = esp32-8048S050N
[env:esp32-8048S050R]
board = esp32-8048S050R
[env:esp32-8048S070C]
board = esp32-8048S070C
[env:esp32-8048S070N]
board = esp32-8048S070N
Though both didn’t change since yesterday so I suppose it is something caused by the reinstallation of platformio? Some path issues ?
The board names you are using do not exist in the espressif32 platform:
UnknownBoard: Unknown board ID 'esp32-2432S024C'
Are you using a modified platform?
“modified” not really, the board definitions are here:
https://github.com/rzeldent/
pretty popular ESP32 backed displays which are sadly not yet in platformio
board definitions in /boards/ parallel to /src/
Ah okay. 
Did you also remove the espressif32 package folder manually?
On a windows system this folder is located at C:\Users\<username>\.platformio\platforms\
yes, removed the whole .patformio path
The error message you describe usually occurs when your main file is named main.c instead of main.cpp - can you please doublecheck this?
Best to also #include <Arduino.h>.
yes it is named main.cpp
@maxgerhardt didn’t really make a difference when it was working, doesn’t make now either, thought that is more arduino specific than ESP32
Can you post the exact project files to the github?
If you do have a src/main.cpp with the empty setup and loop and Arduino include, it can only not work due to some other effect, like, the file is not even compiled due to build src filters, or other very weird things.
This is almost reduced to nothing for the test now, except for the dependencies in the .ini, let me try something different, I’ll just try a new project for another platform and try to compile the “empty” code there.
works for lolin s3 mini though with some “warnings”
.platformio/packages/framework-arduinoespressif32/cores/esp32/esp32-hal-uart.c:149:6: note: declared here
bool uartSetPins(uint8_t uart_num, int8_t rxPin, int8_t txPin, int8_t ctsPin, int8_t rtsPin)
I also have those in the real project though they never were the reason for build errors.
I swapped the ini with my ini now, works so far with the “empty” code. Still no clue what is wrong with the original project but if this works I’ll just paste my stuff over to the newly created.
EDIT: Yes, it worked. So basically created new project with s3mini board instead, copied over ini, src, and board data and it works again. 