# <inttypes.h>

**[<inttypes.h>](https://en.cppreference.com/w/c/header/inttypes)** solves a portability trap: `uint64_t` may be `unsigned long` on one platform and `unsigned long long` on another. The format macros (`PRIu64`, `PRIx64`) expand to the correct `printf`/`scanf` specifier for each platform.

Use `PRIu64`, `PRId64`, etc. instead of guessing `%llu` or `%lu`.

## Example

This example prints fixed-width integers portably using the PRI macros.

```c
// compile: gcc -o inttypesexample inttypesexample.c
// run: ./inttypesexample
// description: portable printf of fixed-width integers

#include <inttypes.h>
#include <stdio.h>

int main() {
    uint8_t a = 255;
    uint32_t b = 0xDEADBEEF;
    uint64_t c = UINT64_MAX;
    int64_t d = INT64_MIN;
    
    printf("uint8:  %" PRIu8 "\n", a);
    printf("uint32: %" PRIu32 " (0x%" PRIx32 ")\n", b, b);
    printf("uint64: %" PRIu64 "\n", c);
    printf("int64:  %" PRId64 "\n", d);
    
    return 0;
}
```

## Common macros

**Format specifiers** (for printf/scanf of fixed-width integers):
- `PRId8`, `PRId16`, `PRId32`, `PRId64`: signed decimal
- `PRIu8`, `PRIu16`, `PRIu32`, `PRIu64`: unsigned decimal
- `PRIx8`, `PRIx16`, `PRIx32`, `PRIx64`: unsigned hex (lowercase)
- `PRIX8`, `PRIX16`, `PRIX32`, `PRIX64`: unsigned hex (uppercase)
- `SCNd8`, `SCNd16`, `SCNd32`, `SCNd64`: scanf format for signed
- `SCNu8`, `SCNu16`, `SCNu32`, `SCNu64`: scanf format for unsigned

**Type limits**:
- `INT8_MAX`, `INT16_MAX`, `INT32_MAX`, `INT64_MAX` and `_MIN` variants
- `UINT8_MAX`, `UINT16_MAX`, `UINT32_MAX`, `UINT64_MAX`