hare

[hare] The Hare programming language
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testaddr.ha (541B)

      1 // SPDX-License-Identifier: MPL-2.0
      2 // (c) Hare authors <https://harelang.org>
      3 
      4 use rt;
      5 
      6 fn isaddrmapped(addr: *opaque) bool = {
      7 	// This is a hack, but it's a common pattern on POSIX for testing the
      8 	// validity of an address.
      9 	static let pipefd: [2]int = [0, 0];
     10 	if (pipefd[0] == 0) {
     11 		match (rt::pipe2(&pipefd, 0)) {
     12 		case rt::errno =>
     13 			return false;
     14 		case void => yield;
     15 		};
     16 	};
     17 
     18 	match (rt::write(pipefd[1], addr, 1)) {
     19 	case let err: rt::errno =>
     20 		assert(err == rt::EFAULT);
     21 		return false;
     22 	case size =>
     23 		return true;
     24 	};
     25 };