# V1097. Line splice results in a character sequence that matches the syntax of a universal-character-name. Using this sequence lead to undefined behavior.

The analyzer has detected a line splicing of the source code (the '\' character at the end of the line) that forms a Unicode character using the syntax of a universal-character-name. According to the standard, such code leads to undefined behavior.

Example:

    void error()
    {
      auto p = "\\
    u0041"; // maybe const char[2] "A" ?
    }

A string literal is assigned to the 'p' pointer. This string literal forms the capital Latin character 'A', using the \u0041 sequence. At the same time, there is line splicing between the '\' and 'u' characters that is combined with another '\' character.

As a result of the second phase of translation the lines of the source code that terminated by the '\' character should be combined into one. This can be used to improve the readability of the code if it is necessary to split a macro or a long string literal across multiple lines. As a result of combining, strings can form escape sequences. However, the standard explicitly declares that using the universal-character-name in this way leads to undefined behavior:

Except for splices reverted in a raw string literal, if a splice results in a character sequence that matches the syntax of a universal-character-name, the behavior is undefined.

To avoid this, the sequence must be completely placed on one line, or moved to another:

    void ok1()
    {
      auto p = "\u0041"; // const char[2] "A"
    }
    void ok2()
    {
      auto p = "\
    \u0041";
    }