Bom dia, error enviar smtp em c++

Estou criando um programa ele da seguinte error


teste.cpp: In function 'int main(int, char**)':
teste.cpp:48:7: warning: case label value exceeds maximum value for type
       case 188:
       ^~~~
teste.cpp:51:7: warning: case label value exceeds maximum value for type
       case 190:
       ^~~~
teste.cpp:69:104: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]
     sendEmail("gmail-smtp-in.l.google.com", "email", "email", "- Log -", buffer);
                                                                                                        ^
teste.cpp:69:104: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]
teste.cpp:69:104: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]
teste.cpp:69:104: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]
C:\Users\Mezzo\AppData\Local\Temp\ccbDhiJg.o:teste.cpp:(.text+0x205): undefined reference to `WSAStartup@8'
C:\Users\Mezzo\AppData\Local\Temp\ccbDhiJg.o:teste.cpp:(.text+0x221): undefined reference to `gethostbyname@4'
C:\Users\Mezzo\AppData\Local\Temp\ccbDhiJg.o:teste.cpp:(.text+0x299): undefined reference to `htons@4'
C:\Users\Mezzo\AppData\Local\Temp\ccbDhiJg.o:teste.cpp:(.text+0x2bf): undefined reference to `socket@12'
C:\Users\Mezzo\AppData\Local\Temp\ccbDhiJg.o:teste.cpp:(.text+0x2e2): undefined reference to `connect@12'
C:\Users\Mezzo\AppData\Local\Temp\ccbDhiJg.o:teste.cpp:(.text+0x324): undefined reference to `send@16'
C:\Users\Mezzo\AppData\Local\Temp\ccbDhiJg.o:teste.cpp:(.text+0x3d8): undefined reference to `send@16'
C:\Users\Mezzo\AppData\Local\Temp\ccbDhiJg.o:teste.cpp:(.text+0x487): undefined reference to `send@16'
C:\Users\Mezzo\AppData\Local\Temp\ccbDhiJg.o:teste.cpp:(.text+0x4dd): undefined reference to `send@16'
C:\Users\Mezzo\AppData\Local\Temp\ccbDhiJg.o:teste.cpp:(.text+0x698): undefined reference to `send@16'
C:\Users\Mezzo\AppData\Local\Temp\ccbDhiJg.o:teste.cpp:(.text+0x6ee): more undefined references to `send@16' follow
C:\Users\Mezzo\AppData\Local\Temp\ccbDhiJg.o:teste.cpp:(.text+0x70e): undefined reference to `closesocket@4'
C:\Users\Mezzo\AppData\Local\Temp\ccbDhiJg.o:teste.cpp:(.text+0x716): undefined reference to `WSACleanup@0'
collect2.exe: error: ld returned 1 exit status

vamos la

vc tem diversos warnings que não são erros, mas o compilador ta dizendo “mano… isso não se faz, ce ta loko meo?”

isso aqui parece um erro

undefined reference to `WSAStartup@8’

O google diz que isso pode ser um erro do MingW de não encontrar a biblioteca Winsock

Se for o caso, vc precisa adicionar enquanto esta compilando uma opção como -lws2_32

fonte: