File: string-literal-with-embedded-nul.rst

package info (click to toggle)
swiftlang 6.0.3-2
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid, trixie
  • size: 2,519,992 kB
  • sloc: cpp: 9,107,863; ansic: 2,040,022; asm: 1,135,751; python: 296,500; objc: 82,456; f90: 60,502; lisp: 34,951; pascal: 19,946; sh: 18,133; perl: 7,482; ml: 4,937; javascript: 4,117; makefile: 3,840; awk: 3,535; xml: 914; fortran: 619; cs: 573; ruby: 573
file content (36 lines) | stat: -rw-r--r-- 1,246 bytes parent folder | download | duplicates (28)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
.. title:: clang-tidy - bugprone-string-literal-with-embedded-nul

bugprone-string-literal-with-embedded-nul
=========================================

Finds occurrences of string literal with embedded NUL character and validates
their usage.

Invalid escaping
----------------

Special characters can be escaped within a string literal by using their
hexadecimal encoding like ``\x42``. A common mistake is to escape them
like this ``\0x42`` where the ``\0`` stands for the NUL character.

.. code-block:: c++

  const char* Example[] = "Invalid character: \0x12 should be \x12";
  const char* Bytes[] = "\x03\0x02\0x01\0x00\0xFF\0xFF\0xFF";

Truncated literal
-----------------

String-like classes can manipulate strings with embedded NUL as they are keeping
track of the bytes and the length. This is not the case for a ``char*``
(NUL-terminated) string.

A common mistake is to pass a string-literal with embedded NUL to a string
constructor expecting a NUL-terminated string. The bytes after the first NUL
character are truncated.

.. code-block:: c++

  std::string str("abc\0def");  // "def" is truncated
  str += "\0";                  // This statement is doing nothing
  if (str == "\0abc") return;   // This expression is always true