5.2.1.1 Trigraph sequences

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232 All occurrences in a source file Before any other processing takes place, each occurrence of one of the following sequences of three characters (called trigraph sequences¹²⁾) are replaced with the corresponding single character.

233

??= #   ??) ]   ??! |
??( [   ??' ^   ??< }
??/ \   ??< {   ??- ~

234 No other trigraph sequences exist.

235 Each ? that does not begin one of the trigraphs listed above is not changed.

236 EXAMPLE 1


       ??=define arraycheck(a,b) a??(b??) ??!??! b??(a??)

becomes


       #define arraycheck(a,b) a[b] || b[a]

237 EXAMPLE 2 The following source line


        printf("Eh???/n");

becomes (after replacement of the trigraph sequence ??/)


        printf("Eh?\n");