For debugging a complicated macro I would like to print out the catcode of a token. Optimally I would like to have a macro \getcatcode such that, for example, \getcatcode{a} would expand to 10. How can this be done?

I found lots of information about how to set/change catcodes, but nothing about how to read them.

  • 3
    BTW: the catcode of a is 11 (letter) not 10 (space). Jun 22, 2011 at 13:22

3 Answers 3


Use \catcode together with \the to get the catcode of the token:


Note: The ` turns the next character into its ASCII number which is required for \catcode.

As custom macro:


Special characters must be escaped with a backslash, e.g. % must be written as \%, # as \# etc. It doesn't hurt to write normal letters the same way, e.g. \getcatcode\a works as well.


As explained in an exercise of the TeXbook one can also write

      beginning of group\or
      end of group\or
      math shift\or
      end of line\or

 The category code is `\printcatcode\%'

Just to point out that any of the "code tables" in TeX can be used to access the value (\catcode, \lccode, \uccode, \mathcode, \delcode, \sfcode).


The solutions offered by Martin and egreg print the current catcode of a character. I understood the original question to be how one can print the catcode of a token, i.e., one that has already been scanned, possibly in the past, when different catcodes were in effect. Consider this:


     \message{The catcode of the ##1 in \noexpand#1 is \getcatcode{##1}.^^J}


Clearly the @s stored in the macros \x and \y have two different catcodes. However, with Martin's macro, we get:

The catcode of the @ in \x  is 12.
The catcode of the @ in \y  is 12.

That is because Martin's macro prints the 'current' catcode of the character represented by the token, rather than the catcode actually stored in the token.

The following is a better solution:

  % locally ensure that characters have their expected catcodes
  \catcode`\ =10%
    \ifcat\noexpand#1 10\else%

With this, we get the expected answer:

The catcode of the @ in \x  is 11.
The catcode of the @ in \y  is 12.

The code is a bit awkward and I wonder if there is a more elegant solution. I was unable to test for catcodes 0, 1, 2, 5, 9, 14, and 15, but I am not sure if such catcodes can actually occur after the input has been tokenized.

  • 1
    Category codes 1 and 2 can certainly exist: think \def\x{{a}} which holds three tokens, {, a and }.
    – Joseph Wright
    Feb 24, 2015 at 14:36

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