What is the best way to set a particular bit in a variable in C

Question

Consider a variable unsigned int a; in C.

Now say I want to set any i\'th bit in this variable to \'1\'.

Note that the variable has some value.

Answer 1

The way I implemented bit flags (to quote straight out of my codebase, you can use it freely for whatever purpose, even commercial):

void SetEnableFlags(int &BitFlags, const int Flags)
{
    BitFlags = (BitFlags|Flags);
}
const int EnableFlags(const int BitFlags, const int Flags)
{
    return (BitFlags|Flags);
}

void SetDisableFlags(int BitFlags, const int Flags)
{
    BitFlags = (BitFlags&(~Flags));
}
const int DisableFlags(const int BitFlags, const int Flags)
{
    return (BitFlags&(~Flags));
}

No bitwise shift operation needed.

You might have to tidy up or alter the code to use the particular variable set you're using, but generally it should work fine.