Compile-time configuration¶

277 MACROS · THREE OWNERS · 53 UNREAD · MEASURING METHOD

The eighty platformio.ini files together define 277 unique -D macros. This chapter sorts them by owner — library, Arduino core or MeshCore itself — and then goes into the most important finding: of the 254 MeshCore macros, 53 are defined and read nowhere.

[!NOTE] Source. This page was verified against the firmware itself: MeshCore v1.16.0, commit 03b6ef4, 28 July 2026 — the root platformio.ini, all 79 variants/*/platformio.ini and the complete source tree under src/, examples/ and variants/.

Three owners¶

A macro belongs to whoever reads it, not to whoever defines it. All 277 are set in MeshCore's own ini files, but they end up with three different parties.

Group	Macros	Read by
1 — library	17	An external library
2 — framework	6	An Arduino core
3 — MeshCore	254	MeshCore's own source files

Three stacks. On the left seventeen macros with an arrow to a block of
external libraries, in the middle six with an arrow to a block of Arduino
cores, on the right two hundred and fifty-four with an arrow to the MeshCore
source tree. From that third stack a portion of fifty-three runs to an empty
field with no reader.

Group 1 is written out in Library configuration, where it belongs: those macros say something about the libraries, not about MeshCore.

Two macros sit commented out and are therefore active in no build: RADIOLIB_DEBUG_BASIC and RADIOLIB_DEBUG_SPI. They are not counted in the 277.

Group 2 — framework (6)¶

Macro	Consumer
`ARDUINO_LOOP_STACK_SIZE`	Arduino-ESP32 core
`ARDUINO_RAKWIRELESS_RAK11300`	arduino-pico core
`ARDUINO_USB_CDC_ON_BOOT`	Arduino-ESP32 core
`ARDUINO_USB_MODE`	Arduino-ESP32 core
`ARDUINO_heltec_wifi_lora_32_V3`	Arduino-ESP32 core
`CORE_DEBUG_LEVEL`	Arduino-ESP32 core

Five of the six are ESP32 macros. That is no accident: the Arduino-ESP32 core lets more be set through build flags than the other three cores do, particularly around USB and the serial-over-USB behaviour at startup.

Group 3 — MeshCore (254)¶

Of the 254 MeshCore macros, 201 are read somewhere in the source tree and 53 nowhere.

The 201 by the place where they first occur:

Where	Macros
`variants/`	48
`src/helpers/ui/`	35
`examples/`	29
`src/helpers/` (core)	28
`src/helpers/sensors/`	28
`src/helpers/esp32,nrf52,stm32/`	21
`src/helpers/radiolib/`	8
`src/`	2
`src/helpers/bridges/`	2

Two macros in src/ — that is the entire core. Everything steerable with a build flag sits in the layers around it. The core itself is not configurable and compiles the same way in every build.

A few examples of places where such a macro is read. These are representative reading places, not necessarily the first occurrence that the table above counts:

Macro	Read in
`ADVERT_NAME`	`examples/simple_repeater/MyMesh.cpp` r.22
`MAX_NEIGHBOURS`	`examples/simple_repeater/MyMesh.cpp` r.64
`DISPLAY_CLASS`	`examples/simple_repeater/main.cpp` r.6
`WITH_RS232_BRIDGE`	`src/helpers/CommonCLI.cpp` r.720
`P_LORA_NSS`	`src/helpers/MeshadventurerBoard.h` r.7

[!NOTE] Measuring method. The distribution table counts per macro the first occurrence of the name in the source tree, traversed in the order src/ → examples/ → variants/ and alphabetically within each directory. That order belongs with the figure: a different traversal order shifts the table by up to 22 macros.

First occurrence is not the same as first read. P_LORA_NSS in MeshadventurerBoard.h r.7 is a #define, so a redefinition and not a test. The macros in the example table above were picked because they are illustrative, not because they are the first occurrence.

The 53 that are read nowhere¶

Twenty-one percent of the MeshCore macros are defined and never tested. They fall into three groups.

Board markers (35)¶

EBYTE_EORA_S3, GENERIC_E22, HELTEC_HT_CT62, HELTEC_LORA_V2, HELTEC_LORA_V3, HELTEC_LORA_V4, HELTEC_MESH_POCKET, HELTEC_T114, HELTEC_WIRELESS_PAPER, KEEPTEEN_LT1, LILYGO_T3S3, LILYGO_TETH_ELITE, LILYGO_TLORA, LILYGO_T_ETH_ELITE_ESP32S3, MESHADVENTURER, MESHTINY, NIBBLE_SCREEN_CONNECT, PROMICRO, RAK_11310, RAK_3112, RAK_3401, RAK_3X72, SEEED_XIAO_S3, STATION_G2, STATION_G3_ESP32, T1000_E, TBEAM_1W, THINKNODE_M2, THINKNODE_M3, THINKNODE_M5, Vision_Master_E213, Vision_Master_E290, WIO_TRACKER_L1, WIRELESS_PAPER, me25ls01.

Every variant file defines its own name as a macro. Nothing tests for it, because the variant already gets its own -I path and therefore sees its own headers. They are documentation in the shape of a macro: you read in the platformio.ini which board it is, and the compiler does nothing with it.

Platform marker (1)¶

ESP32_PLATFORM. The other three platform macros — NRF52_PLATFORM, RP2040_PLATFORM, STM32_PLATFORM — are read; this one is not, because ESP32 code uses the core macro ESP32 that is there anyway. See Platform realisation.

Other (17)¶

BOARD_HAS_PSRAM, DISABLE_DIAGNOSTIC_OUTPUT, DISPLAY_LINES, ENABLE_HWSERIAL2, HAS_NEOPIXEL, HAS_TOUCH, IO_EXPANDER_IRQ, LINE_LENGTH, NDEBUG, NEOPIXEL_COUNT, NEOPIXEL_DATA, NEOPIXEL_TYPE, PIN_SERIAL_RX, PIN_SERIAL_TX, P_LORA_TX_LED_ON, UI_GPS_PAGE, WITH_ESPNOW_BRIDGE_SECRET.

[!IMPORTANT] These seventeen are not all dead. NDEBUG is standard C and is read by the standard library; BOARD_HAS_PSRAM, PIN_SERIAL_RX, PIN_SERIAL_TX and ENABLE_HWSERIAL2 are read by an Arduino core. Those five therefore belong in group 2 and not in group 3. The ownership table NAMESPACES in tools/config-flags.py classifies them wrongly, because it works on name prefix and these five have no recognisable prefix. The script can show them separately as of this delivery, but the classification has not been silently corrected: that calls for a separate decision.

The remaining twelve, among them HAS_NEOPIXEL, NEOPIXEL_COUNT and UI_GPS_PAGE, point at functionality that does not exist in this commit. The build flags are there, the code reacting to them is not — or no longer.

What this means¶

A macro that is read nowhere is not dangerous, but it is misleading. Anyone seeing HAS_TOUCH in a platformio.ini may assume something happens with touch input. It does not.

For anyone adding a board that matters in practice: copying the board marker has no effect, and switching on UI_GPS_PAGE yields no GPS page. What does work is visible in the 201 macros that do have a reader.

Recomputing¶

python3 tools/config-flags.py /path/to/MeshCore
python3 tools/config-flags.py /path/to/MeshCore --owners
python3 tools/config-flags.py /path/to/MeshCore --consumption

--owners writes groups 2 and 3 as a markdown table; --consumption gives per MeshCore macro the first file and line number where it occurs, with an explicit category read nowhere. The script skips lines behind a ;, so that commented-out macros do not inflate the configuration surface.

Sources¶

Translated from Dutch by Anthropic Claude