lvalue compile error

[SeeCwriter]

Why am I getting the compiler error below?

typedef uint8_t byte;

setBit(char *ch, int bitnum, bool set) 
{
  uint8_t mask = 1 << bitnum;

  if ( set )	(byte)*ch |=  mask; // <--- lvalue required as left operand.
  else		(byte)*ch &= ~mask;
}
 

[vlad from moscow]

Expression (byte)*ch is rvalue. You may not assign a value to it. You can write simply

*ch |= mask;

or

*ch = (byte) *ch | mask;

[SeeCwriter]

I originally had

*ch |= mask;

and the compiler complained about an invalid type conversion, unsigned int to char.

I changed the function argument from char to byte to eliminate the error.