Purpose of Trigraph sequences in C++?
- by Kirill V. Lyadvinsky
According to C++'03 Standard 2.3/1:
Before any other processing takes place, each occurrence of one of the following sequences of three characters (“trigraph sequences”) is replaced by the single character indicated in Table 1.
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| trigraph | replacement | trigraph | replacement | trigraph | replacement |
----------------------------------------------------------------------------
| ??= | # | ??( | [ | ??< | { |
| ??/ | \ | ??) | ] | ??> | } |
| ??’ | ˆ | ??! | | | ??- | ˜ |
----------------------------------------------------------------------------
In real life that means that code printf( "What??!\n" ); will result in printing What| because ??! is a trigraph sequence that is replaced with the | character.
My question is what purpose of using trigraphs? Is there any practical advantage of using trigraphs?
UPD: In answers was mentioned that some European keyboards don't have all the punctuation characters, so non-US programmers have to use trigraphs in everyday life?
UPD2: Visual Studio 2010 has trigraph support turned off by default.
