how can i use strset() function in keil string header file
It's not part of the Standard 'C' Library - does Keil provide it?
Err, no, not seeing it.
But surely a trivial exercise to implement.
... and since a 'set needs a 'len, I quickly imagine combining two of the functions to make a strset().
Imagination - or, more specifically, problem-solving ability - seems to be sorely lacking these days...
:-(