Can scanf/sscanf deal with escaped characters?

Question

int main()
{
  char* a = " 'Fools\' day' ";
  char* b[64];
  sscanf(a, " '%[^']s ", b);
  printf ("%s", b);
}

--> puts "Fools" in b

Obviously, I want to have "Fools' day" in b. Can I tell sscanf() not to consider escaped apostrophes as the end of the character sequence?

Thanks!

Answer 1

No. Those functions just read plain old characters. They don't interpret the contents according to any escaping rules because there's nothing to escape from — quotation marks, apostrophes, and backslashes aren't special in the input string.

You'll have to use something else to parse your string. You can write a little state machine to read the string one character at a time, keeping track of whether the previous character was a backslash. (Don't just scan to the next apostrophe and then look one character backward; if you're allowed to escape backslashes as well as apostrophes, then you could end up re-scanning all the way back to the start of the string to see whether you have an odd or even number of escape characters. Always parse strings forward, not backward.)