iocla_printf

A lightweight, custom implementation of the standard printf function in C, supporting basic format specifiers and direct system-level output via write.

Features

• Supports the following format specifiers:

  • %d — Signed decimal integers
  • %u — Unsigned decimal integers
  • %x — Hexadecimal (lowercase)
  • %c — Single characters
  • %s — Null-terminated strings
  • %% — Literal percent sign

• Handles:

  • Negative integers
  • Zero-padding via internal logic
  • Basic string and memory handling without relying on printf

Implementation Details

• Uses write(1, ...) for direct output to stdout
• Manual conversion of integers using custom itoa, utoa, and htoa functions
• Custom string utility functions: strrev, strlwr
• Variable argument processing with stdarg.h

Limitations

• No support for floating-point formats (%f)
• No field width, precision, or flags (e.g. %05d)
• Basic error handling
• Minimal memory safety (relies on manual allocation and freeing)

Example

iocla_printf("Hello, %s! Your score is %d%% (hex: %x)\n", "Alice", 93, 93);

Build & Run

gcc -o printf_example your_file.c
./printf_example