# <stdint.h>

**[<stdint.h>](https://en.cppreference.com/w/c/header/stdint)** provides fixed-width integer types (C99): `int8_t`, `uint32_t`, `int64_t`, etc., guaranteeing exact widths across platforms. Also includes `intmax_t`, `intptr_t`, and limit macros like `INT32_MAX`.

Use fixed-width types for binary I/O, hardware registers, and portable low-level code.

## Example

This example queries the sizes of fixed-width integer types on the platform.

```c
// compile: gcc -o stdintexample stdintexample.c
// run: ./stdintexample
// description: show fixed-width integer type sizes

#include <stdint.h>
#include <stdio.h>

int main() {
    printf("int8_t = %zu bytes\n", sizeof(int8_t));
    printf("int16_t = %zu bytes\n", sizeof(int16_t));
    printf("int32_t = %zu bytes\n", sizeof(int32_t));
    printf("int64_t = %zu bytes\n", sizeof(int64_t));
    printf("intptr_t = %zu bytes\n", sizeof(intptr_t));
    printf("INT32_MAX = %d\n", INT32_MAX);
    printf("UINT64_MAX = %llu\n", (unsigned long long)UINT64_MAX);
    
    return 0;
}
```

## Common types and macros

**Fixed-width signed integers**:
- `int8_t`, `int16_t`, `int32_t`, `int64_t`: exactly N-bit signed integers
- Guaranteed to exist and have exactly that size

**Fixed-width unsigned integers**:
- `uint8_t`, `uint16_t`, `uint32_t`, `uint64_t`: exactly N-bit unsigned integers

**Pointer-sized integers**:
- `intptr_t`, `uintptr_t`: guaranteed to hold any pointer safely
- Use for pointer arithmetic without losing information

**Widest types**:
- `intmax_t`, `uintmax_t`: widest signed and unsigned integers on platform
- May be 64-bit or larger (e.g., 128-bit on some platforms)

**Min/max macros** (INT8_MIN through INT64_MIN, etc.):
- `INT8_MAX`, `INT8_MIN`: ±128 for int8_t
- `INT16_MAX`, `INT16_MIN`: ±32,767 for int16_t
- `INT32_MAX`, `INT32_MIN`: ±2,147,483,647 for int32_t
- `INT64_MAX`, `INT64_MIN`: ±9,223,372,036,854,775,807 for int64_t
- `UINT8_MAX`, `UINT16_MAX`, `UINT32_MAX`, `UINT64_MAX`: unsigned limits
- `INTPTR_MAX`, `UINTPTR_MAX`: pointer limits
- `INTMAX_MAX`, `UINTMAX_MAX`: widest type limits

**Common usage**:
- Use fixed-width types (`uint32_t`, etc.) for binary data, network protocols, hardware interfaces
- Prefer `int`, `unsigned` for general integer arithmetic (these have efficient operations)
- This header is more portable than `<limits.h>` for specific-width guarantees