Compilation of example sketch fails with esp8266 board package version >= 3.0.0

[wuppiwuppi]

Description

Simple compilation of the example sketch fails with the below error.

Workaround:

Install older board package version < 3.0.0
esp8266 by ESP8266 Community Version 2.7.4

Steps To Reproduce Problem

Open example sketch and verify (compile) it.

Hardware & Software

IDE: Arduino 1.8.16 OR Arudino IDE 2.0.0-beta.12
Board: Generic ESP8266
Board: esp8266 by ESP8266 Community Version 3.0.2
ESP01-S
Win11

Arduino Sketch

#include <CapacitiveSensor.h>

/*
 * CapitiveSense Library Demo Sketch
 * Paul Badger 2008
 * Uses a high value resistor e.g. 10M between send pin and receive pin
 * Resistor effects sensitivity, experiment with values, 50K - 50M. Larger resistor values yield larger sensor values.
 * Receive pin is the sensor pin - try different amounts of foil/metal on this pin
 */


CapacitiveSensor   cs_4_2 = CapacitiveSensor(0,2);        // 10M resistor between pins 4 & 2, pin 2 is sensor pin, add a wire and or foil if desired
//CapacitiveSensor   cs_4_6 = CapacitiveSensor(4,6);        // 10M resistor between pins 4 & 6, pin 6 is sensor pin, add a wire and or foil
//CapacitiveSensor   cs_4_8 = CapacitiveSensor(4,8);        // 10M resistor between pins 4 & 8, pin 8 is sensor pin, add a wire and or foil

void setup()                    
{
   cs_4_2.set_CS_AutocaL_Millis(0xFFFFFFFF);     // turn off autocalibrate on channel 1 - just as an example
   Serial.begin(9600);
}

void loop()                    
{
    long start = millis();
    long total1 =  cs_4_2.capacitiveSensor(30);
  //  long total2 =  cs_4_6.capacitiveSensor(30);
  //  long total3 =  cs_4_8.capacitiveSensor(30);

    Serial.print(millis() - start);        // check on performance in milliseconds
    Serial.print("\t");                    // tab character for debug windown spacing

    Serial.print(total1);                  // print sensor output 1
    //Serial.print("\t");
    //Serial.print(total2);                  // print sensor output 2
    //Serial.print("\t");
    //Serial.println(total3);                // print sensor output 3

    delay(10);                             // arbitrary delay to limit data to serial port 
}

Errors or Incorrect Output

Compiling library "CapacitiveSensor-master" "C:\\Users\\xyz\\AppData\\Local\\Arduino15\\packages\\esp8266\\tools\\xtensa-lx106-elf-gcc\\3.0.4-gcc10.3-1757bed/bin/xtensa-lx106-elf-g++" -D__ets__ -DICACHE_FLASH -U__STRICT_ANSI__ -D_GNU_SOURCE "-IC:\\Users\\xyz\\AppData\\Local\\Arduino15\\packages\\esp8266\\hardware\\esp8266\\3.0.2/tools/sdk/include" "-IC:\\Users\\xyz\\AppData\\Local\\Arduino15\\packages\\esp8266\\hardware\\esp8266\\3.0.2/tools/sdk/lwip2/include" "-IC:\\Users\\xyz\\AppData\\Local\\Arduino15\\packages\\esp8266\\hardware\\esp8266\\3.0.2/tools/sdk/libc/xtensa-lx106-elf/include" "-IC:\\Users\\xyz\\AppData\\Local\\Temp\\arduino-sketch-D98C7FED0C5F5F9EA38B42012BE2DB9B/core" -c -Werror=return-type -Os -g -free -fipa-pta -mlongcalls -mtext-section-literals -fno-rtti -falign-functions=4 -std=gnu++17 -MMD -ffunction-sections -fdata-sections -fno-exceptions -DMMU_IRAM_SIZE=0x8000 -DMMU_ICACHE_SIZE=0x8000 -DNONOSDK22x_190703=1 -DF_CPU=80000000L -DLWIP_OPEN_SRC -DTCP_MSS=536 -DLWIP_FEATURES=1 -DLWIP_IPV6=0 -DARDUINO=10607 -DARDUINO_ESP8266_GENERIC -DARDUINO_ARCH_ESP8266 "-DARDUINO_BOARD=\"ESP8266_GENERIC\"" -DLED_BUILTIN=2 -DFLASHMODE_DOUT -DESP8266 "-IC:\\Users\\xyz\\AppData\\Local\\Arduino15\\packages\\esp8266\\hardware\\esp8266\\3.0.2\\cores\\esp8266" "-IC:\\Users\\xyz\\AppData\\Local\\Arduino15\\packages\\esp8266\\hardware\\esp8266\\3.0.2\\variants\\generic" "-Ie:\\Stuff\\Arduino\\projects\\libraries\\CapacitiveSensor-master" "e:\\Stuff\\Arduino\\projects\\libraries\\CapacitiveSensor-master\\CapacitiveSensor.cpp" -o "C:\\Users\\xyz\\AppData\\Local\\Temp\\arduino-sketch-D98C7FED0C5F5F9EA38B42012BE2DB9B\\libraries\\CapacitiveSensor-master\\CapacitiveSensor.cpp.o" e:\Stuff\Arduino\projects\libraries\CapacitiveSensor-master\CapacitiveSensor.cpp: In member function 'long int CapacitiveSensor::capacitiveSensor(uint8_t)': e:\Stuff\Arduino\projects\libraries\CapacitiveSensor-master\CapacitiveSensor.cpp:94:75: error: call of overloaded 'abs(long unsigned int)' is ambiguous 94 | if ( (millis() - lastCal > CS_AutocaL_Millis) && abs(total - leastTotal) < (int)(.10 * (float)leastTotal) ) { | ^ In file included from c:\users\xyz\appdata\local\arduino15\packages\esp8266\tools\xtensa-lx106-elf-gcc\3.0.4-gcc10.3-1757bed\xtensa-lx106-elf\include\c++\10.3.0\cstdlib:75, from c:\users\xyz\appdata\local\arduino15\packages\esp8266\tools\xtensa-lx106-elf-gcc\3.0.4-gcc10.3-1757bed\xtensa-lx106-elf\include\c++\10.3.0\stdlib.h:36, from C:\Users\xyz\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.0.2\cores\esp8266/Arduino.h:27, from e:\Stuff\Arduino\projects\libraries\CapacitiveSensor-master\CapacitiveSensor.cpp:30: c:\users\xyz\appdata\local\arduino15\packages\esp8266\tools\xtensa-lx106-elf-gcc\3.0.4-gcc10.3-1757bed\xtensa-lx106-elf\include\stdlib.h:74:5: note: candidate: 'int abs(int)' 74 | int abs (int); | ^~~ In file included from c:\users\xyz\appdata\local\arduino15\packages\esp8266\tools\xtensa-lx106-elf-gcc\3.0.4-gcc10.3-1757bed\xtensa-lx106-elf\include\c++\10.3.0\cstdlib:77, from c:\users\xyz\appdata\local\arduino15\packages\esp8266\tools\xtensa-lx106-elf-gcc\3.0.4-gcc10.3-1757bed\xtensa-lx106-elf\include\c++\10.3.0\stdlib.h:36, from C:\Users\xyz\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\3.0.2\cores\esp8266/Arduino.h:27, from e:\Stuff\Arduino\projects\libraries\CapacitiveSensor-master\CapacitiveSensor.cpp:30: c:\users\xyz\appdata\local\arduino15\packages\esp8266\tools\xtensa-lx106-elf-gcc\3.0.4-gcc10.3-1757bed\xtensa-lx106-elf\include\c++\10.3.0\bits\std_abs.h:79:3: note: candidate: 'constexpr long double std::abs(long double)' 79 | abs(long double __x) | ^~~ c:\users\xyz\appdata\local\arduino15\packages\esp8266\tools\xtensa-lx106-elf-gcc\3.0.4-gcc10.3-1757bed\xtensa-lx106-elf\include\c++\10.3.0\bits\std_abs.h:75:3: note: candidate: 'constexpr float std::abs(float)' 75 | abs(float __x) | ^~~ c:\users\xyz\appdata\local\arduino15\packages\esp8266\tools\xtensa-lx106-elf-gcc\3.0.4-gcc10.3-1757bed\xtensa-lx106-elf\include\c++\10.3.0\bits\std_abs.h:71:3: note: candidate: 'constexpr double std::abs(double)' 71 | abs(double __x) | ^~~ c:\users\xyz\appdata\local\arduino15\packages\esp8266\tools\xtensa-lx106-elf-gcc\3.0.4-gcc10.3-1757bed\xtensa-lx106-elf\include\c++\10.3.0\bits\std_abs.h:61:3: note: candidate: 'long long int std::abs(long long int)' 61 | abs(long long __x) { return __builtin_llabs (__x); } | ^~~ c:\users\xyz\appdata\local\arduino15\packages\esp8266\tools\xtensa-lx106-elf-gcc\3.0.4-gcc10.3-1757bed\xtensa-lx106-elf\include\c++\10.3.0\bits\std_abs.h:56:3: note: candidate: 'long int std::abs(long int)' 56 | abs(long __i) { return __builtin_labs(__i); } | ^~~ Using library CapacitiveSensor-master at version 0.5.1 in folder: E:\Stuff\Arduino\projects\libraries\CapacitiveSensor-master Compilation error: Error: 13 INTERNAL: exit status 1

[vks007]

I was able to compile and use this for esp8266 by modifying the following line of code in CapacitiveSensor.cpp. The issue here is that abs() function is taking unsigned long as arguments which doesn't make sense.
unsigned long diff = (total > leastTotal) ? total - leastTotal : leastTotal - total;
if ( (millis() - lastCal > CS_AutocaL_Millis) && diff < (int)(.10 * (float)leastTotal) ) {