xref: /llvm-project/clang-tools-extra/docs/clang-tidy/checks/abseil/string-find-startswith.rst (revision bc8cff1d7fb2069aa3f7333e25642f2571049af1)
1.. title:: clang-tidy - abseil-string-find-startswith
2
3abseil-string-find-startswith
4=============================
5
6Checks whether a ``std::string::find()`` or ``std::string::rfind()`` (and
7corresponding ``std::string_view`` methods) result is compared with 0, and
8suggests replacing with ``absl::StartsWith()``. This is both a readability and
9performance issue.
10
11``starts_with`` was added as a built-in function on those types in C++20. If
12available, prefer enabling :doc:`modernize-use-starts-ends-with
13<../modernize/use-starts-ends-with>` instead of this check.
14
15.. code-block:: c++
16
17  string s = "...";
18  if (s.find("Hello World") == 0) { /* do something */ }
19  if (s.rfind("Hello World", 0) == 0) { /* do something */ }
20
21becomes
22
23
24.. code-block:: c++
25
26  string s = "...";
27  if (absl::StartsWith(s, "Hello World")) { /* do something */ }
28  if (absl::StartsWith(s, "Hello World")) { /* do something */ }
29
30
31Options
32-------
33
34.. option:: StringLikeClasses
35
36   Semicolon-separated list of names of string-like classes. By default both
37   ``std::basic_string`` and ``std::basic_string_view`` are considered. The list
38   of methods to be considered is fixed.
39
40.. option:: IncludeStyle
41
42   A string specifying which include-style is used, `llvm` or `google`. Default
43   is `llvm`.
44
45.. option:: AbseilStringsMatchHeader
46
47   The location of Abseil's ``strings/match.h``. Defaults to
48   ``absl/strings/match.h``.
49