Add clang-format

c.md

@@ -9,3 +9,16 @@ int option = 1;
 sockfd = socket(AF_INET, SOCK_STREAM, 0);
 setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option));
 ```
+
+## Formatting
+### `clang-format`
+- Format all files in-place: `clang-format -i *.c *.h`
+- Specify format:
+    - Predefined style: `-style=<STYLE>`, e.g. `-style=llvm`
+    - Custom file in current or parent directory: `-style=file`
+- Create style file based on default: `clang-format -style=llvm -dump-config > .clang-format`
+- If no `-style` is provided, `-style=file` is used. If there is no `.clang-format`, `-style=LLVM` is used
+- Use default style, but overwrite some key: `--style={BasedOnStyle: <STYLE>, <KEY>: <VALUE>}`
+
+### Example
+- `clang-format --style="{BasedOnStyle: LLVM, IndentWidth: 4, ColumnLimit: 90}" -i *.c *.h`