printf.ts
899dad6b8a9etype-hints-typescript

printf.ts
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			import { dlopen, suffix, FFIType } from 'ant:ffi';

			let libcName: string;
			if (process.platform === 'darwin') {
			libcName = `libSystem.${suffix}`;
			} else if (process.platform === 'linux') {
			libcName = `libc.${suffix}`;
			} else if (process.platform === 'win32') {
			libcName = `msvcrt.${suffix}`;
			} else throw new Error(`Unsupported platform: ${process.platform}`);

			interface libC {
			putchar(c: number): number;
			printf(format: string, ...args: unknown[]): number;
			}

			const libc = dlopen<libC>(libcName);

			libc.define('putchar', {
			args: [FFIType.int],
			returns: FFIType.int
			});

			libc.define('printf', {
			args: [FFIType.string, FFIType.spread],
			returns: FFIType.int
			});

			console.log(libc);

			console.log('calling putchar(65):');
			libc.putchar(65); // 'A'

			console.log('\ncalling printf:');
			libc.printf('Hello FFI! I see %d\n', 42);

			console.log('calling putchar(66):');
			libc.call('putchar', 66); // 'B'