ezprintf

A tiny, header-only C library that provides explicit format-argument binding for standard printf using preprocessor tuples.

Instead of writing a single, detached format string followed by a separate list of arguments, ezprintf allows you to associate format specifiers directly with their corresponding values using short, type-aware macros (like _i32(10) or _x16("04", 123)).

Why?

In standard C, keeping a long printf format string in sync with its arguments is error-prone and hard to read, especially when dealing with fixed-width integers and PRI* macros from <inttypes.h>.

Standard way:

printf("Values: %" PRIu8 " %0*" PRIx32 "\n", 255, 8, 0xdead);

With ezprintf:

ezprintf("Values: ", _u8(255), " ", _x32("0*", 8, 0xdead), "\n");

It makes it immediately clear which format belongs to which argument.

How It Works

At compile time, ezprintf processes the arguments as preprocessor tuples:

1. Bare string literals (like "text") are automatically wrapped into tuples.
2. The MAP macro separates all format fragments from their arguments.
3. String literal concatenation merges all format fragments into a single string.
4. The remaining arguments are unpacked and passed directly into a standard printf call.

Usage Example

#include <stdio.h>
#include "ezprintf.h"

int main(void) {
    // 1. Explicit binding for fixed-width types
    ezprintf("test ", _i32(10), "\n");
    // Expands to: printf("test %" PRId32 "\n", 10);

    // 2. Handling custom formatting flags (width and padding)
    ezprintf(_x16("04", 123), "\n");
    // Expands to: printf("%04" PRIx16 "\n", 123);

    // 3. Mixing with standard printf tuple syntax if needed
    ezprintf(("Hello, %s!\n", "world"));
    // Expands to: printf("Hello, %s!\n", "world");

    return 0;
}

Supported Macros

The library provides wrappers for all standard PRI* macros from <inttypes.h> for signed/unsigned decimals, octals, hexadecimals, fast/least types, and pointers:

• _d8(...) to _d64(...), _dPTR(...), _dMAX(...)
• _i8(...) to _i64(...), _iPTR(...), _iMAX(...)
• _u8(...) to _u64(...), _uPTR(...), _uMAX(...)
• _x8(...) to _x64(...), _xPTR(...), _xMAX(...)
• _X8(...) to _X64(...), _XPTR(...), _XMAX(...)
• _o8(...) to _o64(...), _oPTR(...), _oMAX(...)

Dependencies & Compatibility

• C99 or later (requires variadic macros).
• GCC or Clang (relies on the GNU extension , ##__VA_ARGS__ for empty argument elimination).
• map-macro.h by William R. Swanson (included in the repository).

License

This is free and unencumbered software released into the public domain. For details, see the header or UNLICENSE.