# <wchar.h>

**[<wchar.h>](https://en.cppreference.com/w/c/header/wchar)** provides wide-character functions (C95): `wprintf`, `wcslen`, `wcscmp`, etc. The encoding of `wchar_t` is platform-dependent (UTF-32 on Linux, UTF-16 on Windows), making portable Unicode code difficult.

For portable Unicode, prefer `<uchar.h>` with `char32_t` (UTF-32) or `char16_t` (UTF-16).

## Example

This example demonstrates wide-string handling and locale-aware output.

```c
// compile: gcc -o wcharexample wcharexample.c
// run: ./wcharexample
// description: wide string handling and character counting

#include <wchar.h>
#include <locale.h>
#include <string.h>
#include <stdio.h>

int main() {
    setlocale(LC_ALL, "");
    
    const wchar_t* ws = L"héllo";
    const char* ns = "héllo";
    
    wprintf(L"wide string: %ls\n", ws);
    wprintf(L"wcslen: %zu (wchar units)\n", wcslen(ws));
    printf("strlen: %zu (bytes)\n", strlen(ns));
    printf("sizeof(wchar_t): %zu\n", sizeof(wchar_t));
    
    return 0;
}
```

## Common functions

**String length and comparison**:
- `wcslen(s)`: length of wide string
- `wcscmp(s1, s2)`: compare wide strings
- `wcsncmp(s1, s2, n)`: compare first n wide characters
- `wcscoll(s1, s2)`: compare with locale
- `wcsxfrm(d, s, n)`: transform for sorting

**String copying and concatenation**:
- `wcscpy(d, s)`: copy wide string
- `wcsncpy(d, s, n)`: copy up to n characters
- `wcscat(d, s)`: append wide string
- `wcsncat(d, s, n)`: append up to n characters

**String searching**:
- `wcschr(s, c)`: find wide character in string
- `wcsrchr(s, c)`: find last occurrence
- `wcspbrk(s, accept)`: find first of accept chars
- `wcsspn(s, accept)`: length of prefix in accept
- `wcscspn(s, reject)`: length of prefix not in reject
- `wcsstr(s, sub)`: find substring

**Output/input**:
- `wprintf(fmt, ...)`: wide character formatted print
- `fwprintf(f, fmt, ...)`: wide printf to file
- `wscanf(fmt, ...)`: wide scanf
- `fwscanf(f, fmt, ...)`: wide scanf from file