1.. title:: clang-tidy - bugprone-string-literal-with-embedded-nul
2
3bugprone-string-literal-with-embedded-nul
4=========================================
5
6Finds occurrences of string literal with embedded NUL character and validates
7their usage.
8
9Invalid escaping
10----------------
11
12Special characters can be escaped within a string literal by using their
13hexadecimal encoding like ``\x42``. A common mistake is to escape them
14like this ``\0x42`` where the ``\0`` stands for the NUL character.
15
16.. code-block:: c++
17
18  const char* Example[] = "Invalid character: \0x12 should be \x12";
19  const char* Bytes[] = "\x03\0x02\0x01\0x00\0xFF\0xFF\0xFF";
20
21Truncated literal
22-----------------
23
24String-like classes can manipulate strings with embedded NUL as they are keeping
25track of the bytes and the length. This is not the case for a ``char*``
26(NUL-terminated) string.
27
28A common mistake is to pass a string-literal with embedded NUL to a string
29constructor expecting a NUL-terminated string. The bytes after the first NUL
30character are truncated.
31
32.. code-block:: c++
33
34  std::string str("abc\0def");  // "def" is truncated
35  str += "\0";                  // This statement is doing nothing
36  if (str == "\0abc") return;   // This expression is always true
37