ดูจาก error น่าจะมาจาก Library MicroGear เป็นรุ่นเก่าไม่ตรงกับ code ครับ  

โค้ดขึ้น Error แบบนี้ต้องทำไงครับ Arduino:1.8.19 (Windows 10), บอร์ด:"Generic ESP8266 Module, 80 MHz, Flash, Disabled (new aborts on oom), Disabled, All SSL ciphers (most compatible), 32KB cache + 32KB IRAM (balanced), Use pgm_read macros for IRAM/PROGMEM, dtr (aka nodemcu), 26 MHz, 40MHz, DOUT (compatible), 1MB (FS:64KB OTA:~470KB), 2, nonos-sdk 2.2.1+100 (190703), v2 Lower Memory, Disabled, None, Only Sketch, 115200" C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\PubSubClient.cpp: In member function 'virtual boolean PubSubClient::subscribe(const char*, uint8_t)': C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\PubSubClient.cpp:474:13: warning: comparison is always false due to limited range of data type [-Wtype-limits] 474 | if (qos < 0 || qos > 1) { | ~~~~^~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp: In function 'void msgCallback(char*, uint8_t*, unsigned int)': C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:21:28: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 21 | cb_present("present",payload,length); | ^~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:26:27: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 26 | cb_absent("absent",payload,length); | ^~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:39:26: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 39 | cb_error("error",payload,length); | ^~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:44:25: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 44 | cb_info("info",payload,length); | ^~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp: In member function 'void MicroGear::resetEndpoint()': C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:104:17: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 104 | writeEEPROM("",EEPROM_ENDPOINTSOFFSET,1); | ^~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp: In member function 'void AuthClient::writeout(char*, bool, bool)': C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:48:13: warning: unused variable 'ch' [-Wunused-variable] 48 | uint8_t ch, buff[MAXHEADERLINESIZE]; | ^~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:46:57: warning: unused parameter 'progmem' [-Wunused-parameter] 46 | void AuthClient::writeout(char* str, bool newline, bool progmem) { | ~~~~~^~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp: In member function 'void MicroGear::syncTime(Client*, long unsigned int*)': C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:151:22: error: 'class BearSSL::WiFiClientSecure' has no member named 'verify' 151 | if (clientsecure->verify(tstr, gearauth)) { | ^~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp: In member function 'void MicroGear::on(unsigned char, void (*)(char*, uint8_t*, unsigned int))': C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:236:31: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 236 | subscribe("/&present"); | ^~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:241:31: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 241 | subscribe("/&absent"); | ^~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp: In member function 'bool MicroGear::getToken(char*, char*, char*, char*, char*)': C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:397:130: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 397 | authstatus = authclient->getGearToken(_ACCESSTOKEN,token,tokensecret,endpoint,flag,gearkey,gearsecret,galias,"",rtoken,rtokensecret); | ^~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp: In member function 'int MicroGear::connectBroker(char*)': C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:515:9: warning: deleting object of polymorphic class type 'MQTTClient' which has non-virtual destructor might cause undefined behavior [-Wdelete-non-virtual-dtor] 515 | delete(mqttclient); | ^~~~~~~~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:570:35: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 570 | subscribe("/&present"); | ^~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:572:35: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 572 | subscribe("/&absent"); | ^~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp: In member function 'bool MicroGear::publish(char*, String, String)': C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:676:14: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 676 | strcat(top,"/"); | ^~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp: In member function 'bool MicroGear::publish(char*, String, char*)': C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:690:11: warning: comparison with string literal results in unspecified behavior [-Waddress] 690 | if(apikey!=""){ | ~~~~~~^~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:691:14: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 691 | strcat(top,"/"); | ^~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp: In member function 'bool MicroGear::writeFeed(char*, char*, char*)': C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:702:15: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 702 | strcat(buff,"/"); | ^~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp: In member function 'void MicroGear::setAlias(char*)': C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:745:17: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 745 | publish(top,""); | ^~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp: In function 'bool processTok(char*, char*, char**)': C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:117:23: warning: value computed is not used [-Wunused-value] 117 | if (**p=='&') *p++; | ^~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp: In member function 'void AuthClient::addParam(char*, char*, char*, bool)': C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:135:29: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 135 | if (!first) strcat(buff,"%26"); | ^~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:137:17: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 137 | strcat(buff,"%3D"); | ^~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp: In member function 'int MicroGear::init(char*, char*)': C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:783:29: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 783 | init(gearkey,gearsecret,"",""); | ^~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:783:32: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 783 | init(gearkey,gearsecret,"",""); | ^~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:784:1: error: no return statement in function returning non-void [-Werror=return-type] 784 | } | ^ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp: In member function 'int MicroGear::init(char*, char*, char*)': C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:787:39: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 787 | init(gearkey,gearsecret,gearalias,""); | ^~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:788:1: error: no return statement in function returning non-void [-Werror=return-type] 788 | } | ^ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp: In member function 'int MicroGear::init(char*, char*, char*, char*)': C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:800:1: error: no return statement in function returning non-void [-Werror=return-type] 800 | } | ^ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp: In member function 'int AuthClient::getGearToken(char, char*, char*, char*, char*, char*, char*, char*, char*, char*, char*)': C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:180:21: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 180 | writeln("POST /api/rtoken HTTP/1.1"); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:181:29: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 181 | strcat(signbase,"%2Fapi%2Frtoken&"); | ^~~~~~~~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:184:21: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 184 | writeln("POST /api/atoken HTTP/1.1"); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:185:29: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 185 | strcat(signbase,"%2Fapi%2Fatoken&"); | ^~~~~~~~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:190:15: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 190 | write("Authorization: OAuth "); | ^~~~~~~~~~~~~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:161:34: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 161 | #define OAUTH_CALLBACK "oauth_callback=" | ^~~~~~~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:195:21: note: in expansion of macro 'OAUTH_CALLBACK' 195 | append(buff,OAUTH_CALLBACK,0); | ^~~~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:196:21: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 196 | strcat(buff,"\"appid%3D"); | ^~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:199:21: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 199 | strcat(buff,"%26mgrev%3D"); | ^~~~~~~~~~~~~ In file included from C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:7: C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.h:18:15: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 18 | #define MGREV "E8A1b" | ^~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:200:21: note: in expansion of macro 'MGREV' 200 | strcat(buff,MGREV); | ^~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:204:21: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 204 | strcat(buff,"%26scope%3D"); | ^~~~~~~~~~~~~ In file included from C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:7: C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.h:18:15: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 18 | #define MGREV "E8A1b" | ^~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:213:29: note: in expansion of macro 'MGREV' 213 | strcat(verifier,MGREV); | ^~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:216:21: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 216 | strcat(buff,"%26verifier%3D"); | ^~~~~~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:218:21: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 218 | strcat(buff,"\","); | ^~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:161:34: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 161 | #define OAUTH_CALLBACK "oauth_callback=" | ^~~~~~~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:222:21: note: in expansion of macro 'OAUTH_CALLBACK' 222 | append(buff,OAUTH_CALLBACK,0); | ^~~~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:227:23: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 227 | addParam(buff,"appid",appid,1); | ^~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:228:23: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 228 | addParam(buff,"mgrev",MGREV,0); | ^~~~~~~ In file included from C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:7: C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.h:18:15: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 18 | #define MGREV "E8A1b" | ^~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:228:31: note: in expansion of macro 'MGREV' 228 | addParam(buff,"mgrev",MGREV,0); | ^~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:229:23: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 229 | addParam(buff,"scope",scope,0); | ^~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:230:23: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 230 | addParam(buff,"verifier",verifier,0); | ^~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:162:38: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 162 | #define OAUTH_CONSUMER_KEY "oauth_consumer_key=" | ^~~~~~~~~~~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:235:21: note: in expansion of macro 'OAUTH_CONSUMER_KEY' 235 | append(buff,OAUTH_CONSUMER_KEY,0); | ^~~~~~~~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:238:21: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 238 | strcat(buff,"\""); | ^~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:240:21: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 240 | strcat(buff,"\""); | ^~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:242:25: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 242 | strcat(signbase,"%26"); //& | ^~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:245:21: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 245 | strcat(buff,","); | ^~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:262:25: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 262 | strcat(signbase,"%26"); //& | ^~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:265:21: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 265 | strcat(buff,","); | ^~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:271:25: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 271 | strcat(signbase,"%26"); //& | ^~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:274:21: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 274 | strcat(buff,","); | ^~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:284:25: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 284 | strcat(signbase,"%26"); //& | ^~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:287:21: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 287 | strcat(buff,","); | ^~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:295:29: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 295 | strcat(signbase,"%26"); //& | ^~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:298:25: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 298 | strcat(buff,","); | ^~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:305:29: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 305 | strcat(signbase,"%26"); //& | ^~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:308:25: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 308 | strcat(buff,","); | ^~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:315:25: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 315 | strcat(signbase,"%26"); //& | ^~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:318:21: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 318 | strcat(buff,","); | ^~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:333:21: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 333 | strcat(buff,"\""); | ^~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:335:21: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 335 | strcat(buff,"\r\n"); | ^~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:338:17: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 338 | writeln("Accept: */*"); | ^~~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:339:17: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 339 | writeln("Connection: close"); | ^~~~~~~~~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:340:17: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 340 | writeln("User-Agent: E8A"); | ^~~~~~~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:341:17: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 341 | writeln("Content-length: 0"); | ^~~~~~~~~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:342:17: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] 342 | writeln("Content-Type: application/x-www-form-urlencoded"); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:352:14: warning: unused variable 'pline' [-Wunused-variable] 352 | char pline = 0; | ^~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp: In member function 'char* AuthClient::encode(char*, char)': C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:402:19: warning: suggest parentheses around '&&' within '||' [-Wparentheses] 402 | if ('0' <= ch && ch <= '9' || 'a' <= ch && ch <= 'z' || 'A' <= ch && ch <= 'Z' || ch == '-' || ch == '.' || ch == '_' || ch == '~') { | ~~~~~~~~~~^~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\AuthClient.cpp:402:71: warning: suggest parentheses around '&&' within '||' [-Wparentheses] 402 | if ('0' <= ch && ch <= '9' || 'a' <= ch && ch <= 'z' || 'A' <= ch && ch <= 'Z' || ch == '-' || ch == '.' || ch == '_' || ch == '~') { | ~~~~~~~~~~^~~~~~~~~~~~ C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp: In member function 'int MicroGear::connectBroker(char*)': C:\Users\DELL\Documents\Arduino\libraries\ESP8266_Microgear\MicroGear.cpp:589:1: error: control reaches end of non-void function [-Werror=return-type] 589 | } | ^ cc1plus.exe: some warnings being treated as errors exit status 1 Error compiling for board Generic ESP8266 Module. This report would have more information with "Show verbose output during compilation" option enabled in File -> Preferences.