Undefined Reference in main.o (IDFGH-6246)

Environment

Development Kit: [ESP32-DevKitC]
Kit version (for WroverKit/PicoKit/DevKitC): [No Clue]
Module or chip used: [No Clue]
IDF version (run git describe --tags to find it) [not a git directory]: 4.3.1 // v3.2-dev-1148-g96cd3b75c
Build System: [CMake]
Compiler version (run xtensa-esp32-elf-gcc --version to find it) [invalid command]: espressif32 3.4.0
Operating System: [Windows]
(Windows only) environment type: [PlatformIO].
Using an IDE?: [Visual Studio Code]
Power Supply: [N/A]

Problem Description

Attempted re-creation of PPPoS utility results in failure to compile due to undefined reference.

Here is the single line of code causing this issue.

Here is the error message: c:/users/user/.platformio/packages/toolchain-xtensa-esp32/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: .pio\build\esp32dev\src\main.o:(.literal.app_main+0x40): undefined reference to_g_esp_netif_netstack_default_ppp' collect2.exe: error: ld returned 1 exit status`

Changing the single line of code causing this issue to the following allows for full compilation of code: esp_netif_config_t cfg;

Expected Behavior

Copying 99% of example code (replacing placeholders) compiles with minimal modification (12 total modified lines).

Actual Behavior

Copying 99% of example code (replacing placeholders) causes compilation error unless further modified.

Steps to reproduce

Copy code from this file into main.c
Replace EXAMPLE variables and other placeholders with static data (int, string, etc.)
Compile project

// If possible, attach a picture of your setup/wiring here.

Don't think I can do that

Code to reproduce this issue is found here

Debug Logs

Compiling .pio\build\esp32dev\src\main.o
Linking .pio\build\esp32dev\firmware.elf
c:/users/user/.platformio/packages/toolchain-xtensa-esp32/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: .pio\build\esp32dev\src\main.o:(.literal.app_main+0x40): undefined reference to `_g_esp_netif_netstack_default_ppp'
collect2.exe: error: ld returned 1 exit status
*** [.pio\build\esp32dev\firmware.elf] Error 1

Other items if possible

[x] sdkconfig file (attach the sdkconfig file from your project folder) sdkconfig.txt
[x] elf file in the build folder (note this may contain all the code details and symbols of your project.) Can't do that
[x] coredump (This provides stacks of tasks.) Don't think I can do that

Hi @JsMailhot

Thanks for reporting this issue.

Changing the single line of code causing this issue to the following allows for full compilation of code: esp_netif_config_t cfg;

So, if I understand correctly this example: https://github.com/espressif/esp-idf/blob/release/v4.3/examples/protocols/pppos_client/main/pppos_client_main.c compiles okay, until you change this line, correct? Would you mind sharing that line of code, your modification, that causes this linker problem, so we can reproduce the problem?

Please note that even the default config should reference the _g_esp_netif_netstack_default_ppp symbol via:

https://github.com/espressif/esp-idf/blob/98d34e5f6db8904c31bd1e372d9896e4931d7a9b/components/esp_netif/include/esp_netif_defaults.h#L121-L126

https://github.com/espressif/esp-idf/blob/98d34e5f6db8904c31bd1e372d9896e4931d7a9b/components/esp_netif/include/esp_netif_defaults.h#L169

So, if I understand correctly this example: https://github.com/espressif/esp-idf/blob/release/v4.3/examples/protocols/pppos_client/main/pppos_client_main.c compiles okay, until you change this line, correct? Would you mind sharing that line of code, your modification, that causes this linker problem, so we can reproduce the problem?

Reading that back, my wording was a little confusing, let me rephrase. This line of code causes a compile error for me. When I run my code, I get the following error message:

c:/users/user/.platformio/packages/toolchain-xtensa-esp32/bin/../lib/gcc/xtensa-esp32-elf/8.4.0/../../../../xtensa-esp32-elf/bin/ld.exe: .pio\build\esp32dev\src\main.o:(.literal.app_main+0x40): undefined reference to _g_esp_netif_netstack_default_ppp

I figure that this is the line of code causing the compilation error, because when I change it from this:

esp_netif_config_t cfg = ESP_NETIF_DEFAULT_PPP();

To this:

esp_netif_config_t cfg;

It compiles! I have not tested the functionality of the upload however, as I suspected there I wouldn't have to change that line to get it to compile. Rather my issue had something to do with the ESP_NETIF_DEFAULT_PPP(); function. The only other lines of code that I have changed to the example implementation are some of the static example variables:

config.tx_io_num = 3; config.rx_io_num = 2; config.rts_io_num = 1; config.cts_io_num = 0; config.rx_buffer_size = 1024; config.tx_buffer_size = 1024; config.pattern_queue_size = 30; config.event_queue_size = 30; config.event_task_stack_size = 2048; config.event_task_priority = 5; config.line_buffer_size = 512;

But I don't think these changes have anything to do with the issue.

I did find these definitions for what my compiler is claiming to be an undefined reference, so it is clearly there but it appears as though it is not being seen. I thought it might be a versioning issue, maybe my compiler is trying to use a different version installed, but even after uninstalling other versions and setting my PlatformIO environment to use specifically this one and it still appears to be unable to find it. I am not certain how to proceed further to diagnose the reason for my compiler not seeing this code that I would think to be available to it, or if that is even really what is going on. As I have never come across an issue like this, and I haven't found much success in following other similar issues to undefined references.

Thank you for the feedback and assistance!

Oh, I see, so in fact you're not able to compile the default example with PlatformIO, correct?

Could you please post the linker command that links the application? It's usually the very long, last line that ends with -o pppos_client.elf, just before the error message.

This error typically happens when linking multiple components with unclear or mutually related dependency tree. I believe however, that this should never exhibit in IDF build system as the main.o is treated as the most top-level component. Understanding how the components are built on PlatformIO would help.

Thank you for your suggestion, I am going to do more looking into that today. That's my current situation, yes. I have never dealt directly with the linker commands because they are generated automatically, but I was able to collect the following by using the pio run -v command in my visual studio terminal.

Using tempfile C:\Users\user\Documents\GitHub\project\esp-idf\.pio\build\esp32dev\tmp_mzmmbv9.tmp for command line: xtensa-esp32-elf-gcc -o .pio/build/esp32dev/src/main.o -c -std=gnu99 -mlongcalls -Wno-frame-address -ffunction-sections -fdata-sections -Wall -Werror=all -Wno-error=unused-function -Wno-error=unused-variable -Wno-error=deprecated-declarations -Wextra -Wno-unused-parameter -Wno-sign-compare -ggdb -Og -fstrict-volatile-bitfields -Wno-error=unused-but-set-variable -Wno-old-style-declaration -DPLATFORMIO=50203 -DARDUINO_ESP32_DEV -D_GNU_SOURCE -DIDF_VER=\"4.3.1\" -DESP_PLATFORM -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_pm/include -I.pio/build/esp32dev/config -IC:/Users/user/.platformio/packages/framework-espidf/components/newlib/platform_include -IC:/Users/user/.platformio/packages/framework-espidf/components/freertos/include -IC:/Users/user/.platformio/packages/framework-espidf/components/freertos/port/xtensa/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_hw_support/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_hw_support/port/esp32 -IC:/Users/user/.platformio/packages/framework-espidf/components/heap/include -IC:/Users/user/.platformio/packages/framework-espidf/components/log/include -IC:/Users/user/.platformio/packages/framework-espidf/components/lwip/include/apps -IC:/Users/user/.platformio/packages/framework-espidf/components/lwip/include/apps/sntp -IC:/Users/user/.platformio/packages/framework-espidf/components/lwip/lwip/src/include -IC:/Users/user/.platformio/packages/framework-espidf/components/lwip/port/esp32/include -IC:/Users/user/.platformio/packages/framework-espidf/components/lwip/port/esp32/include/arch -IC:/Users/user/.platformio/packages/framework-espidf/components/soc/include -IC:/Users/user/.platformio/packages/framework-espidf/components/soc/esp32 -IC:/Users/user/.platformio/packages/framework-espidf/components/soc/esp32/include -IC:/Users/user/.platformio/packages/framework-espidf/components/hal/esp32/include -IC:/Users/user/.platformio/packages/framework-espidf/components/hal/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_rom/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_rom/esp32 -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_rom/include/esp32 -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_common/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_system/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp32/include -IC:/Users/user/.platformio/packages/framework-espidf/components/driver/include -IC:/Users/user/.platformio/packages/framework-espidf/components/driver/esp32/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_ringbuf/include -IC:/Users/user/.platformio/packages/framework-espidf/components/efuse/include -IC:/Users/user/.platformio/packages/framework-espidf/components/efuse/esp32/include -IC:/Users/user/.platformio/packages/framework-espidf/components/xtensa/include -IC:/Users/user/.platformio/packages/framework-espidf/components/xtensa/esp32/include -IC:/Users/user/.platformio/packages/framework-espidf/components/espcoredump/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_timer/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_ipc/include -IC:/Users/user/.platformio/packages/framework-espidf/components/vfs/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_wifi/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_wifi/esp32/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_event/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_netif/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_eth/include -IC:/Users/user/.platformio/packages/framework-espidf/components/tcpip_adapter/include -IC:/Users/user/.platformio/packages/framework-espidf/components/app_trace/include -IC:/Users/user/.platformio/packages/framework-espidf/components/mbedtls/port/include -IC:/Users/user/.platformio/packages/framework-espidf/components/mbedtls/mbedtls/include -IC:/Users/user/.platformio/packages/framework-espidf/components/mbedtls/esp_crt_bundle/include -IC:/Users/user/.platformio/packages/framework-espidf/components/app_update/include -IC:/Users/user/.platformio/packages/framework-espidf/components/spi_flash/include -IC:/Users/user/.platformio/packages/framework-espidf/components/bootloader_support/include -IC:/Users/user/.platformio/packages/framework-espidf/components/nvs_flash/include -IC:/Users/user/.platformio/packages/framework-espidf/components/pthread/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_gdbstub/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_gdbstub/xtensa -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_gdbstub/esp32 -IC:/Users/user/.platformio/packages/framework-espidf/components/wpa_supplicant/include -IC:/Users/user/.platformio/packages/framework-espidf/components/wpa_supplicant/port/include -IC:/Users/user/.platformio/packages/framework-espidf/components/wpa_supplicant/include/esp_supplicant -IC:/Users/user/.platformio/packages/framework-espidf/components/perfmon/include -IC:/Users/user/.platformio/packages/framework-espidf/components/asio/asio/asio/include -IC:/Users/user/.platformio/packages/framework-espidf/components/asio/port/include -IC:/Users/user/.platformio/packages/framework-espidf/components/cbor/port/include -IC:/Users/user/.platformio/packages/framework-espidf/components/unity/include -IC:/Users/user/.platformio/packages/framework-espidf/components/unity/unity/src -IC:/Users/user/.platformio/packages/framework-espidf/components/cmock/CMock/src -IC:/Users/user/.platformio/packages/framework-espidf/components/coap/port/include -IC:/Users/user/.platformio/packages/framework-espidf/components/coap/port/include/coap -IC:/Users/user/.platformio/packages/framework-espidf/components/coap/libcoap/include -IC:/Users/user/.platformio/packages/framework-espidf/components/coap/libcoap/include/coap2 -IC:/Users/user/.platformio/packages/framework-espidf/components/console -IC:/Users/user/.platformio/packages/framework-espidf/components/nghttp/port/include -IC:/Users/user/.platformio/packages/framework-espidf/components/nghttp/nghttp2/lib/includes -IC:/Users/user/.platformio/packages/framework-espidf/components/esp-tls -IC:/Users/user/.platformio/packages/framework-espidf/components/esp-tls/esp-tls-crypto -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_adc_cal/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_hid/include -IC:/Users/user/.platformio/packages/framework-espidf/components/tcp_transport/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_http_client/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_http_server/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_https_ota/include -IC:/Users/user/.platformio/packages/framework-espidf/components/protobuf-c/protobuf-c -IC:/Users/user/.platformio/packages/framework-espidf/components/protocomm/include/common -IC:/Users/user/.platformio/packages/framework-espidf/components/protocomm/include/security -IC:/Users/user/.platformio/packages/framework-espidf/components/protocomm/include/transports -IC:/Users/user/.platformio/packages/framework-espidf/components/mdns/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_local_ctrl/include -IC:/Users/user/.platformio/packages/framework-espidf/components/sdmmc/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_serial_slave_link/include -IC:/Users/user/.platformio/packages/framework-espidf/components/esp_websocket_client/include -IC:/Users/user/.platformio/packages/framework-espidf/components/expat/expat/expat/lib -IC:/Users/user/.platformio/packages/framework-espidf/components/expat/port/include -IC:/Users/user/.platformio/packages/framework-espidf/components/wear_levelling/include -IC:/Users/user/.platformio/packages/framework-espidf/components/fatfs/diskio -IC:/Users/user/.platformio/packages/framework-espidf/components/fatfs/vfs -IC:/Users/user/.platformio/packages/framework-espidf/components/fatfs/src -IC:/Users/user/.platformio/packages/framework-espidf/components/freemodbus/common/include -IC:/Users/user/.platformio/packages/framework-espidf/components/idf_test/include -IC:/Users/user/.platformio/packages/framework-espidf/components/idf_test/include/esp32 -IC:/Users/user/.platformio/packages/framework-espidf/components/jsmn/include -IC:/Users/user/.platformio/packages/framework-espidf/components/json/cJSON -IC:/Users/user/.platformio/packages/framework-espidf/components/libsodium/libsodium/src/libsodium/include -IC:/Users/user/.platformio/packages/framework-espidf/components/libsodium/port_include -IC:/Users/user/.platformio/packages/framework-espidf/components/mqtt/esp-mqtt/include -IC:/Users/user/.platformio/packages/framework-espidf/components/openssl/include -IC:/Users/user/.platformio/packages/framework-espidf/components/spiffs/include -IC:/Users/user/.platformio/packages/framework-espidf/components/ulp/include -IC:/Users/user/.platformio/packages/framework-espidf/components/wifi_provisioning/include -Iinclude -Isrc -Ilib/LED -Ilib/LTE_Tracker -Ilib/bg96 -Ilib/esp_modem -Ilib/esp_modem_netif -Ilib/hts221 -Ilib/i2c_bus -Ilib/lis2dh12 -Ilib/sim7600 -Ilib/sim800 src/main.c xtensa-esp32-elf-gcc @C:\Users\user\Documents\GitHub\project\esp-idf\.pio\build\esp32dev\tmp_mzmmbv9.tmp xtensa-esp32-elf-gcc -o .pio\build\esp32dev\firmware.elf -T esp32_out.ld -u esp_app_desc -u pthread_include_pthread_impl -u pthread_include_pthread_cond_impl -u pthread_include_pthread_local_storage_impl -u ld_include_panic_highint_hdl -u start_app -u start_app_other_cores -T esp32.rom.ld -T esp32.rom.api.ld -T esp32.rom.libgcc.ld -T esp32.rom.newlib-data.ld -T esp32.rom.syscalls.ld -T esp32.rom.newlib-funcs.ld -T esp32.rom.newlib-time.ld -u vfs_include_syscalls_impl -T esp32.project.ld -T esp32.peripherals.ld -u call_user_start_cpu0 -u app_main -u newlib_include_heap_impl -u newlib_include_syscalls_impl -u newlib_include_pthread_impl -u __cxa_guard_dummy -u __cxx_fatal_exception -Wl,--Map=C:/Users/user/Documents/GitHub/project/esp-idf/.pio/build/esp32dev/esp-idf.map -Wl,--cref -Wl,--gc-sections -Wl,--undefined=uxTopUsedPriority -Wl,--wrap=_Unwind_Backtrace -Wl,--wrap=_Unwind_DeleteException -Wl,--wrap=_Unwind_FindEnclosingFunction -Wl,--wrap=_Unwind_Find_FDE -Wl,--wrap=_Unwind_ForcedUnwind -Wl,--wrap=_Unwind_GetCFA -Wl,--wrap=_Unwind_GetDataRelBase -Wl,--wrap=_Unwind_GetGR -Wl,--wrap=_Unwind_GetIP -Wl,--wrap=_Unwind_GetIPInfo -Wl,--wrap=_Unwind_GetLanguageSpecificData -Wl,--wrap=_Unwind_GetRegionStart -Wl,--wrap=_Unwind_GetTextRelBase -Wl,--wrap=_Unwind_RaiseException -Wl,--wrap=_Unwind_Resume -Wl,--wrap=_Unwind_Resume_or_Rethrow -Wl,--wrap=_Unwind_SetEnableExceptionFdeSorting -Wl,--wrap=_Unwind_SetGR -Wl,--wrap=_Unwind_SetIP -Wl,--wrap=__cxa_call_unexpected -Wl,--wrap=__deregister_frame_info -Wl,--wrap=__deregister_frame_info_bases -Wl,--wrap=__gxx_personality_v0 -Wl,--wrap=__register_frame -Wl,--wrap=__register_frame_info -Wl,--wrap=__register_frame_info_bases -Wl,--wrap=__register_frame_info_table -Wl,--wrap=__register_frame_info_table_bases -Wl,--wrap=__register_frame_table -Wl,--wrap=longjmp -Wl,--wrap=mbedtls_mpi_exp_mod -Wno-frame-address -fno-lto -fno-rtti -mlongcalls .pio\build\esp32dev\src\main.o .pio\build\esp32dev\.pio\build\esp32dev\ca_cert.pem.o -L.pio\build\esp32dev -LC:\Users\user\.platformio\packages\framework-espidf\components\esp_wifi\lib\esp32 -LC:\Users\user\.platformio\packages\framework-espidf\components\esp_rom\esp32\ld -LC:\Users\user\.platformio\packages\framework-espidf\components\esp_wifi\lib\esp32 -LC:\Users\user\.platformio\packages\framework-espidf\components\xtensa\esp32 -L.pio\build\esp32dev\esp-idf\esp32 -L.pio\build\esp32dev\esp-idf\esp32\ld -LC:\Users\user\.platformio\packages\framework-espidf\components\esp32\ld -Wl,--start-group .pio\build\esp32dev\lib7f7\libesp_modem_netif.a .pio\build\esp32dev\libe33\libesp_modem.a .pio\build\esp32dev\lib187\libbg96.a .pio\build\esp32dev\lib1f2\libi2c_bus.a .pio\build\esp32dev\lib1ad\libhts221.a .pio\build\esp32dev\lib542\liblis2dh12.a .pio\build\esp32dev\lib38c\libLED.a .pio\build\esp32dev\libe4e\libLTE_Tracker.a .pio\build\esp32dev\lib3d3\libsim7600.a .pio\build\esp32dev\libaa6\libsim800.a .pio\build\esp32dev\esp-idf\esp_pm\libesp_pm.a .pio\build\esp32dev\esp-idf\asio\libasio.a .pio\build\esp32dev\esp-idf\coap\libcoap.a .pio\build\esp32dev\esp-idf\cbor\libcbor.a .pio\build\esp32dev\esp-idf\unity\libunity.a .pio\build\esp32dev\esp-idf\cmock\libcmock.a .pio\build\esp32dev\esp-idf\console\libconsole.a .pio\build\esp32dev\esp-idf\esp_adc_cal\libesp_adc_cal.a .pio\build\esp32dev\esp-idf\esp_hid\libesp_hid.a .pio\build\esp32dev\esp-idf\esp_local_ctrl\libesp_local_ctrl.a .pio\build\esp32dev\esp-idf\protobuf-c\libprotobuf-c.a .pio\build\esp32dev\esp-idf\mdns\libmdns.a .pio\build\esp32dev\esp-idf\protocomm\libprotocomm.a .pio\build\esp32dev\esp-idf\esp_websocket_client\libesp_websocket_client.a .pio\build\esp32dev\esp-idf\expat\libexpat.a .pio\build\esp32dev\esp-idf\wear_levelling\libwear_levelling.a .pio\build\esp32dev\esp-idf\fatfs\libfatfs.a .pio\build\esp32dev\esp-idf\freemodbus\libfreemodbus.a .pio\build\esp32dev\esp-idf\jsmn\libjsmn.a .pio\build\esp32dev\esp-idf\libsodium\liblibsodium.a .pio\build\esp32dev\esp-idf\openssl\libopenssl.a .pio\build\esp32dev\esp-idf\json\libjson.a .pio\build\esp32dev\esp-idf\mqtt\libmqtt.a .pio\build\esp32dev\esp-idf\spiffs\libspiffs.a .pio\build\esp32dev\esp-idf\wifi_provisioning\libwifi_provisioning.a .pio\build\esp32dev\esp-idf\app_trace\libapp_trace.a .pio\build\esp32dev\esp-idf\app_update\libapp_update.a .pio\build\esp32dev\esp-idf\bootloader_support\libbootloader_support.a .pio\build\esp32dev\esp-idf\cxx\libcxx.a .pio\build\esp32dev\esp-idf\driver\libdriver.a .pio\build\esp32dev\esp-idf\efuse\libefuse.a .pio\build\esp32dev\esp-idf\esp-tls\libesp-tls.a .pio\build\esp32dev\esp-idf\esp32\libesp32.a .pio\build\esp32dev\esp-idf\esp_common\libesp_common.a .pio\build\esp32dev\esp-idf\esp_eth\libesp_eth.a .pio\build\esp32dev\esp-idf\esp_event\libesp_event.a .pio\build\esp32dev\esp-idf\esp_gdbstub\libesp_gdbstub.a .pio\build\esp32dev\esp-idf\esp_http_client\libesp_http_client.a .pio\build\esp32dev\esp-idf\esp_http_server\libesp_http_server.a .pio\build\esp32dev\esp-idf\esp_https_ota\libesp_https_ota.a .pio\build\esp32dev\esp-idf\esp_hw_support\libesp_hw_support.a .pio\build\esp32dev\esp-idf\esp_ipc\libesp_ipc.a .pio\build\esp32dev\esp-idf\esp_netif\libesp_netif.a .pio\build\esp32dev\esp-idf\esp_ringbuf\libesp_ringbuf.a .pio\build\esp32dev\esp-idf\esp_rom\libesp_rom.a .pio\build\esp32dev\esp-idf\esp_serial_slave_link\libesp_serial_slave_link.a .pio\build\esp32dev\esp-idf\esp_system\libesp_system.a .pio\build\esp32dev\esp-idf\esp_timer\libesp_timer.a .pio\build\esp32dev\esp-idf\esp_wifi\libesp_wifi.a .pio\build\esp32dev\esp-idf\espcoredump\libespcoredump.a .pio\build\esp32dev\esp-idf\freertos\libfreertos.a .pio\build\esp32dev\esp-idf\hal\libhal.a .pio\build\esp32dev\esp-idf\heap\libheap.a .pio\build\esp32dev\esp-idf\log\liblog.a .pio\build\esp32dev\esp-idf\lwip\liblwip.a .pio\build\esp32dev\esp-idf\mbedtls\libmbedtls.a .pio\build\esp32dev\esp-idf\newlib\libnewlib.a .pio\build\esp32dev\esp-idf\nghttp\libnghttp.a .pio\build\esp32dev\esp-idf\nvs_flash\libnvs_flash.a .pio\build\esp32dev\esp-idf\perfmon\libperfmon.a .pio\build\esp32dev\esp-idf\pthread\libpthread.a .pio\build\esp32dev\esp-idf\sdmmc\libsdmmc.a .pio\build\esp32dev\esp-idf\soc\libsoc.a .pio\build\esp32dev\esp-idf\spi_flash\libspi_flash.a .pio\build\esp32dev\esp-idf\tcp_transport\libtcp_transport.a .pio\build\esp32dev\esp-idf\tcpip_adapter\libtcpip_adapter.a .pio\build\esp32dev\esp-idf\ulp\libulp.a .pio\build\esp32dev\esp-idf\vfs\libvfs.a .pio\build\esp32dev\esp-idf\wpa_supplicant\libwpa_supplicant.a .pio\build\esp32dev\esp-idf\xtensa\libxtensa.a .pio\build\esp32dev\esp-idf\mbedtls\mbedtls\library\libmbedcrypto.a .pio\build\esp32dev\esp-idf\mbedtls\mbedtls\library\libmbedtls.a .pio\build\esp32dev\esp-idf\mbedtls\mbedtls\library\libmbedx509.a -lcoexist -lcore -lespnow -lmesh -lnet80211 -lpp -lsmartconfig -lwapi -lphy -lrtc -lxt_hal -lc -lm -lstdc++ -lgcc -Wl,--end-group

Though this may not be what you are looking for as it does not contain any mention of -o pppos_client.elf, this is what prints directly before the error message. In this verbose command response I noticed that there were some circular dependencies with the libraries provided in the example. Specifically the esp_modem_netif and esp_modem files, but this also occurs when I modify that one line as mentioned earlier, and does not prevent compilation. So I do not think that this has anything to do with the issue either.

I will have to do some reading up on the linker command context to understand it better. But I have a feeling that it is the correct direction to be looking for the issue. Thanks again!

Thanks for sharing the command line, yes (part of it) shows the linking phase. There's no -o pppos_client.elf, as it's apparently built a bit differently under PlatformIO and the linker output is -o .pio\build\esp32dev\firmware.elf and (as we suspected) the main component gets also built differently, not as a static library, but linked directly as the object file: main.o.

Can you please try to add this line to your main component makefile?

target_link_libraries(${COMPONENT_LIB} INTERFACE "-u _g_esp_netif_netstack_default_ppp")

just after the idf_component_register() in your project's main/CMakeLists.txt ?

Most certainly, Here is what my CMakeLists.txt file looks like:

set(app_sources "main.c" ) idf_component_register(SRCS ${app_sources}) target_link_libraries(${COMPONENT_LIB} INTERFACE "-u _g_esp_netif_netstack_default_ppp")

After cleaning and compiling again, this is what I get from running the pio run -v command:

xtensa-esp32-elf-gcc -o .pio\build\esp32dev\firmware.elf -T esp32_out.ld -u esp_app_desc -u pthread_include_pthread_impl -u pthread_include_pthread_cond_impl -u pthread_include_pthread_local_storage_impl -u ld_include_panic_highint_hdl -u start_app -u start_app_other_cores -T esp32.rom.ld -T esp32.rom.api.ld -T esp32.rom.libgcc.ld -T esp32.rom.newlib-data.ld -T esp32.rom.syscalls.ld -T esp32.rom.newlib-funcs.ld -T esp32.rom.newlib-time.ld -u vfs_include_syscalls_impl -T esp32.project.ld -T esp32.peripherals.ld -u call_user_start_cpu0 -u app_main -u newlib_include_heap_impl -u newlib_include_syscalls_impl -u newlib_include_pthread_impl -u __cxa_guard_dummy -u __cxx_fatal_exception -u _g_esp_netif_netstack_default_ppp -Wl,--Map=C:/Users/user/Documents/GitHub/project/esp-idf/.pio/build/esp32dev/esp-idf.map -Wl,--cref -Wl,--gc-sections -Wl,--undefined=uxTopUsedPriority -Wl,--wrap=_Unwind_Backtrace -Wl,--wrap=_Unwind_DeleteException -Wl,--wrap=_Unwind_FindEnclosingFunction -Wl,--wrap=_Unwind_Find_FDE -Wl,--wrap=_Unwind_ForcedUnwind -Wl,--wrap=_Unwind_GetCFA -Wl,--wrap=_Unwind_GetDataRelBase -Wl,--wrap=_Unwind_GetGR -Wl,--wrap=_Unwind_GetIP -Wl,--wrap=_Unwind_GetIPInfo -Wl,--wrap=_Unwind_GetLanguageSpecificData -Wl,--wrap=_Unwind_GetRegionStart -Wl,--wrap=_Unwind_GetTextRelBase -Wl,--wrap=_Unwind_RaiseException -Wl,--wrap=_Unwind_Resume -Wl,--wrap=_Unwind_Resume_or_Rethrow -Wl,--wrap=_Unwind_SetEnableExceptionFdeSorting -Wl,--wrap=_Unwind_SetGR -Wl,--wrap=_Unwind_SetIP -Wl,--wrap=__cxa_call_unexpected -Wl,--wrap=__deregister_frame_info -Wl,--wrap=__deregister_frame_info_bases -Wl,--wrap=__gxx_personality_v0 -Wl,--wrap=__register_frame -Wl,--wrap=__register_frame_info -Wl,--wrap=__register_frame_info_bases -Wl,--wrap=__register_frame_info_table -Wl,--wrap=__register_frame_info_table_bases -Wl,--wrap=__register_frame_table -Wl,--wrap=longjmp -Wl,--wrap=mbedtls_mpi_exp_mod -Wno-frame-address -fno-lto -fno-rtti -mlongcalls .pio\build\esp32dev\src\main.o .pio\build\esp32dev\.pio\build\esp32dev\ca_cert.pem.o -L.pio\build\esp32dev -LC:\Users\user\.platformio\packages\framework-espidf\components\esp_wifi\lib\esp32 -LC:\Users\user\.platformio\packages\framework-espidf\components\esp_rom\esp32\ld -LC:\Users\user\.platformio\packages\framework-espidf\components\esp_wifi\lib\esp32 -LC:\Users\user\.platformio\packages\framework-espidf\components\xtensa\esp32 -L.pio\build\esp32dev\esp-idf\esp32 -L.pio\build\esp32dev\esp-idf\esp32\ld -LC:\Users\user\.platformio\packages\framework-espidf\components\esp32\ld -Wl,--start-group .pio\build\esp32dev\lib7f7\libesp_modem_netif.a .pio\build\esp32dev\libe33\libesp_modem.a .pio\build\esp32dev\lib187\libbg96.a .pio\build\esp32dev\lib1f2\libi2c_bus.a .pio\build\esp32dev\lib1ad\libhts221.a .pio\build\esp32dev\lib542\liblis2dh12.a .pio\build\esp32dev\lib38c\libLED.a .pio\build\esp32dev\libe4e\libLTE_Tracker.a .pio\build\esp32dev\lib3d3\libsim7600.a .pio\build\esp32dev\libaa6\libsim800.a .pio\build\esp32dev\esp-idf\esp_pm\libesp_pm.a .pio\build\esp32dev\esp-idf\cmock\libcmock.a .pio\build\esp32dev\esp-idf\cbor\libcbor.a .pio\build\esp32dev\esp-idf\asio\libasio.a .pio\build\esp32dev\esp-idf\unity\libunity.a .pio\build\esp32dev\esp-idf\coap\libcoap.a .pio\build\esp32dev\esp-idf\console\libconsole.a .pio\build\esp32dev\esp-idf\esp_hid\libesp_hid.a .pio\build\esp32dev\esp-idf\esp_adc_cal\libesp_adc_cal.a .pio\build\esp32dev\esp-idf\protobuf-c\libprotobuf-c.a .pio\build\esp32dev\esp-idf\mdns\libmdns.a .pio\build\esp32dev\esp-idf\protocomm\libprotocomm.a .pio\build\esp32dev\esp-idf\esp_local_ctrl\libesp_local_ctrl.a .pio\build\esp32dev\esp-idf\esp_websocket_client\libesp_websocket_client.a .pio\build\esp32dev\esp-idf\expat\libexpat.a .pio\build\esp32dev\esp-idf\wear_levelling\libwear_levelling.a .pio\build\esp32dev\esp-idf\freemodbus\libfreemodbus.a .pio\build\esp32dev\esp-idf\jsmn\libjsmn.a .pio\build\esp32dev\esp-idf\fatfs\libfatfs.a .pio\build\esp32dev\esp-idf\json\libjson.a .pio\build\esp32dev\esp-idf\spiffs\libspiffs.a .pio\build\esp32dev\esp-idf\openssl\libopenssl.a .pio\build\esp32dev\esp-idf\libsodium\liblibsodium.a .pio\build\esp32dev\esp-idf\mqtt\libmqtt.a .pio\build\esp32dev\esp-idf\wifi_provisioning\libwifi_provisioning.a .pio\build\esp32dev\esp-idf\app_trace\libapp_trace.a .pio\build\esp32dev\esp-idf\app_update\libapp_update.a .pio\build\esp32dev\esp-idf\bootloader_support\libbootloader_support.a .pio\build\esp32dev\esp-idf\cxx\libcxx.a .pio\build\esp32dev\esp-idf\driver\libdriver.a .pio\build\esp32dev\esp-idf\efuse\libefuse.a .pio\build\esp32dev\esp-idf\esp-tls\libesp-tls.a .pio\build\esp32dev\esp-idf\esp32\libesp32.a .pio\build\esp32dev\esp-idf\esp_common\libesp_common.a .pio\build\esp32dev\esp-idf\esp_eth\libesp_eth.a .pio\build\esp32dev\esp-idf\esp_event\libesp_event.a .pio\build\esp32dev\esp-idf\esp_gdbstub\libesp_gdbstub.a .pio\build\esp32dev\esp-idf\esp_http_client\libesp_http_client.a .pio\build\esp32dev\esp-idf\esp_http_server\libesp_http_server.a .pio\build\esp32dev\esp-idf\esp_https_ota\libesp_https_ota.a .pio\build\esp32dev\esp-idf\esp_hw_support\libesp_hw_support.a .pio\build\esp32dev\esp-idf\esp_ipc\libesp_ipc.a .pio\build\esp32dev\esp-idf\esp_netif\libesp_netif.a .pio\build\esp32dev\esp-idf\esp_ringbuf\libesp_ringbuf.a .pio\build\esp32dev\esp-idf\esp_rom\libesp_rom.a .pio\build\esp32dev\esp-idf\esp_serial_slave_link\libesp_serial_slave_link.a .pio\build\esp32dev\esp-idf\esp_system\libesp_system.a .pio\build\esp32dev\esp-idf\esp_timer\libesp_timer.a .pio\build\esp32dev\esp-idf\esp_wifi\libesp_wifi.a .pio\build\esp32dev\esp-idf\espcoredump\libespcoredump.a .pio\build\esp32dev\esp-idf\freertos\libfreertos.a .pio\build\esp32dev\esp-idf\hal\libhal.a .pio\build\esp32dev\esp-idf\heap\libheap.a .pio\build\esp32dev\esp-idf\log\liblog.a .pio\build\esp32dev\esp-idf\lwip\liblwip.a .pio\build\esp32dev\esp-idf\mbedtls\libmbedtls.a .pio\build\esp32dev\esp-idf\newlib\libnewlib.a .pio\build\esp32dev\esp-idf\nghttp\libnghttp.a .pio\build\esp32dev\esp-idf\nvs_flash\libnvs_flash.a .pio\build\esp32dev\esp-idf\perfmon\libperfmon.a .pio\build\esp32dev\esp-idf\pthread\libpthread.a .pio\build\esp32dev\esp-idf\sdmmc\libsdmmc.a .pio\build\esp32dev\esp-idf\soc\libsoc.a .pio\build\esp32dev\esp-idf\spi_flash\libspi_flash.a .pio\build\esp32dev\esp-idf\tcp_transport\libtcp_transport.a .pio\build\esp32dev\esp-idf\tcpip_adapter\libtcpip_adapter.a .pio\build\esp32dev\esp-idf\ulp\libulp.a .pio\build\esp32dev\esp-idf\vfs\libvfs.a .pio\build\esp32dev\esp-idf\wpa_supplicant\libwpa_supplicant.a .pio\build\esp32dev\esp-idf\xtensa\libxtensa.a .pio\build\esp32dev\esp-idf\mbedtls\mbedtls\library\libmbedcrypto.a .pio\build\esp32dev\esp-idf\mbedtls\mbedtls\library\libmbedtls.a .pio\build\esp32dev\esp-idf\mbedtls\mbedtls\library\libmbedx509.a -lcoexist -lcore -lespnow -lmesh -lnet80211 -lpp -lsmartconfig -lwapi -lphy -lrtc -lxt_hal -lc -lm -lstdc++ -lgcc -Wl,--end-group

I get the exact same error message on compiling however. Thanks again for the help figuring this out.

Thanks again for testing it, I can see that the linker flag is correctly propagated to the command line, but I don't understand why it could not link or find the symbol. I think I would need to know more about the PlatformIO build process...

Thought I would just test how that example compiles, this is what I tried (Apologies if some of the steps below wasn't according to the best practices for PlatformIO)

Created a new project based on ESP32-pico-kit
Configure the project (enabled lwip->PPP options -- I can see this part was correct in your project)
Replaced the main file
- Copy pasted the IDF example to PlatformIO/Projects/my_project/src/main.c
- Removed all irrelevant #ifdef's
- Replaced all CONFIG_... options to hardcoded values (as you did in your example above)
Created new library in PlatformIO/Projects/my_project/lib called modem
- Copied the entire modem component from https://github.com/espressif/esp-idf/tree/master/examples/protocols/pppos_client/components/modem
- Moved private include to lib-includes (this file )
- Replace the modem configuration with the actual values (setting the APN)
Build the project

And surprisingly, everything compiled and linked

david@Davids-MBP:~/Documents/PlatformIO/Projects/test32$ pio run -v
Processing pico32 (platform: espressif32; board: pico32; framework: espidf)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
CONFIGURATION: https://docs.platformio.org/page/boards/espressif32/pico32.html
PLATFORM: Espressif 32 (3.4.0) > ESP32 Pico Kit
HARDWARE: ESP32 240MHz, 320KB RAM, 4MB Flash
DEBUG: Current (esp-prog) External (esp-prog, iot-bus-jtag, jlink, minimodule, olimex-arm-usb-ocd, olimex-arm-usb-ocd-h, olimex-arm-usb-tiny-h, olimex-jtag-tiny, tumpa)
PACKAGES:
 - framework-espidf 3.40301.0 (4.3.1)
...
Reading CMake configuration...
LDF: Library Dependency Finder -> https://bit.ly/configure-pio-ldf
LDF Modes: Finder ~ chain, Compatibility ~ soft
Found 1 compatible libraries
Scanning dependencies...
Dependency Graph
|-- <modem> (/Users/david/Documents/PlatformIO/Projects/test32/lib/modem)
Building in release mode
<lambda>(["checkprogsize"], [".pio/build/pico32/firmware.elf"])
Advanced Memory Usage is available via "PlatformIO Home > Project Inspect"
RAM:   [=         ]   5.5% (used 17896 bytes from 327680 bytes)
Flash: [======    ]  58.4% (used 612341 bytes from 1048576 bytes)
...
======================================================================================= [SUCCESS] Took 15.32 seconds =======================================================================================

There must be something you have done differently, could you please share the step how you setup the project?

Certainly, it is very odd, and I am 100% certain now that it is something in my personal setup that is causing this issue. I asked another person to attempt to download my project and run it on their machine, they got the same results you did, no compilation errors or concerns of any kind. Here are the steps they followed:

Download project folder
Install Visual Studio Code latest
Install PlatformIO latest
Hit compile (platformio.ini has config...)

Here is the platformio.ini file: [env:esp32dev] platform = espressif32@3.4.0 board = esp32dev framework = espidf monitor_speed = 115200

Compile successfully

Here are the steps that I took to produce this project:

Create new project on Visual Studio Code
Create platformio.ini file as above
Copy this code into my main.c file
Copy example libraries into their respective locations
Replace example variables with static test variables
Compile failure

Since it is certain now that the issue is with my setup rather than esp-idf, I think I will move to the forums for further support on determining where I have made a mistake. Thank you again for your help and looking into this with me. Stay safe and happy coding!

espressif / esp-idf