// stdio.h
struct FILE;
extern static stdin  *FILE,
              stdout *FILE,
              stderr *FILE;
extern fn printf(fmt *const u8, ...) int;
extern fn fprintf(fp *FILE, fmt *const u8, ...) int;
extern fn sprintf(*u8, fmt *const u8, ...) int;
extern fn snprintf(*u8, usize, fmt *const u8, ...) int;
extern fn fopen(path *const u8, mode *const u8) *FILE;
extern fn fclose(*FILE) int;
extern fn fgetc(*FILE) int;
extern fn fputc(int, *FILE) int;
extern fn fread(*void, usize, usize, *FILE) usize;
extern fn fwrite(*void, usize, usize, *FILE) usize;
def SEEK_SET = 0;
extern fn fseek(*FILE, off c_long, whence int) int;
extern fn ftell(*FILE) c_long;
extern fn feof(*FILE) intbool;
def EOF = -1;

// stdlib.h
extern fn abort() void;
extern fn exit(c int) void;
extern fn perror(s *const u8) void;
extern fn malloc(n usize) *void;
extern fn calloc(n usize, m usize) *void;
extern fn realloc(p *void, n usize) *void;
extern fn free(p *void) void;

// string.h
extern fn strlen(s *const u8) usize;
extern fn strcmp(a *const u8, b *const u8) int;
extern fn memcpy(*void, *const void, usize) *void;
extern fn strcpy(*u8, *const u8) *u8;

//ctype.h
extern fn tolower(int) int;