# Extra Clang Tools 22.1.2 documentation

## clang-tidy - readability-uppercase-literal-suffix

# readability-uppercase-literal-suffix

cert-dcl16-c redirects here as an alias for this check. By default, only the suffixes that begin with `l` (`l`, `ll`, `lu`, `llu`, but not `u`, `ul`, `ull`) are diagnosed by that alias.

hicpp-uppercase-literal-suffix redirects here as an alias for this check.

Detects when the integral literal or floating point (decimal or hexadecimal) literal has a non-uppercase suffix and provides a fix-it hint with the uppercase suffix.

All valid combinations of suffixes are supported.

    auto x = 1;  // OK, no suffix.

    auto x = 1u; // warning: integer literal suffix 'u' is not upper-case

    auto x = 1U; // OK, suffix is uppercase.

    ...

## Options

NewSuffixes

  Optionally, a list of the destination suffixes can be provided. When the suffix is found, a case-insensitive lookup in that list is made, and if a replacement is found that is different from the current suffix, then the diagnostic is issued. This allows for fine-grained control of what suffixes to consider and what their replacements should be.

### Example

Given a list L;uL:

- `l` -> `L`

- `L` will be kept as is.

- `ul` -> `uL`

- `Ul` -> `uL`

- `UL` -> `uL`

- `uL` will be kept as is.

- `ull` will be kept as is, since it is not in the list

- and so on.

IgnoreMacros

  If this option is set to true (default is true), the check will not warn about literal suffixes inside macros.