sscanf format

[mjpearson]

I've been reading about sscanf and it's ability to parse strings. I'm now very confused about the proper usage.

I want to parse a full file name string into independent name and respective extension but the proper syntax eludes me. I keep getting confused.

I figure that it needs to look something like this but it doesn't appear to work properly:

sscanf( full_filename, "%[^.]s.%s", filename, extension );

Can someone help me the proper usage of the "[" and"[^" ?

mike

 

[Salem]

[ is a scan set, meaning you want to match a particular set of characters
^ means NOT (anything which doesn't match the set)

So %[^.]s.%s matches a string of characters which are not ., followed by a literal ., then an ordinary string (delimited by whitespace)

Note if you have first.second.ext it will match the FIRST . and not the last.



--
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.

 

[mjpearson]

Thank you. I played with it for a while and got some strange result UNTIL I figured out that I had improperly defined the extension string. I forgot that the string "extension" has to be 4 char long rather than 3. I had forgotten to make room for the trailing "\0".

In the end, the code looked like this:

i = sscanf( argv[1], "%[^.].%s", filename, extension );

It'll take a while but someday this stuff will come easier to me.

thanks again,

mike

 

[ArkM]

Be careful, it's not so easy:
- max extension part length exceeeds 3 on Windows, Unix and Linux
- that's correct file name on these systems: one.two.three
- there are file names without extensions
Moral: sscanf is not an adequate tool for file name parsing.