Fine, but just my Two suggestions:
1-#defines should be used in place of "magic numbers".
2-Missing check of tmp against NULL pointer. tolower(tmp[0]) with tmp pointing NULL crashes.

Learned a lot from this, thank you :D

Great demonstration of a bitfield, and clever use of the hexadecimal number as a mask to determine if any bit in the bitfield is 0.

I really enjoyed reading through your solution. That's great!

I for the love me can't understand how this one ain't the most upvoted both as clever and best practices

hats off for avoiding regex altogether, I tried the same and had 10x the numer of locs

Good point, I don't remember if I did this for a good reason, but given that I initialize bits to 0 I think that & may be superfluous.

can you explain this please ?

Great point, I swing languages very often and some don't have that notation so that betrayed me here

I would have voted for best practices if 'a' was used instead of 97 etc...

For the C version:

• meaning of arguments should be properly documented
• return value should be properly documented (there is a typo which makes things worse)
• the test code should not be so generic, it is very cumbersome to read and understand
• does not specify what to return if there are only T or F values

Thanks for the link!