libc - Freestanding standard library

Makar ships a minimal freestanding C library (libc/) that provides just enough of the standard C interface for the kernel to compile against. It is not a full POSIX libc - it exists solely to satisfy the #include dependencies of the kernel and its subdirectories.

Modules

Header Source(s) Description
stdio.h stdio/printf.c, putchar.c, puts.c Formatted and character output.
stdlib.h stdlib/abort.c Abnormal termination.
string.h string/mem*.c, strlen.c Memory and string utilities.
sys/cdefs.h - Compiler/libc identification macros.

sys/cdefs.h 

#define __makar_libc 1

Identifies this as the Makar freestanding libc. Code that needs to detect the Makar environment at compile time can test #ifdef __makar_libc.

Design notes

  • All sources are compiled with -ffreestanding - no hosted runtime is available.
  • putchar is the single output primitive; printf and puts are built on top of it. The kernel’s tty.c supplies the concrete putchar implementation via the linker.
  • No dynamic memory allocation (malloc/free) is provided here; the kernel’s own kmalloc/kfree heap is used instead.
  • No floating-point, no locale, no signal handling, no file I/O beyond the terminal.

Future work

  • Add <stdarg.h>-compatible vprintf / snprintf for safer formatted output in kernel subsystems.
  • Extend printf to support %d, %u, %x, %p format specifiers fully.
  • Consider a kernel-space <errno.h> for richer error reporting from syscall stubs.

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