SHT21 Soft i2c Libraries

the one I saw which would be to change

virtual void write(byte);

to

virtual void write(byte, strlen(byte));

from what I understood did not work which is why i am asking
I then get the error

/Applications/Arduino v1.0.app/Contents/Resources/Java/libraries/Ports/Ports.h:239: error: 'strlen' is not a type