std: File, the first user of drops: std.Host.open(path, mode) returns an owned std.File (or null) with write and read, and its drop closes the descriptor; Host.writefile is built on it; file_drop.zc, learn and readme

1 files changed, 19 insertions, 0 deletions

diff --git a/tests/programs/file_drop.zc b/tests/programs/file_drop.zc
new file mode 100644
index 0000000..0c0738a
--- /dev/null
+++ b/tests/programs/file_drop.zc
@@ -0,0 +1,19 @@
+namespace;
+// std.File: Host.open gives an owned file whose drop closes the descriptor at its block end (a write to it then writes nothing)
+include rt, std;
+fn main() {
+	int fd = 0 - 1;
+	{
+		std.File* f = std.Host.open("/tmp/zc-file-drop.txt", 1);
+		fd = f.fd;
+		rt.put_n(f.write("hello")); rt.put_c(' ');
+		rt.put_n(rt.syscall(rt.SYS_WRITE, fd, "!", 1)); rt.put_c(' ');
+	}
+	rt.put_n(rt.syscall(rt.SYS_WRITE, fd, "?", 1) <= 0); rt.put_c(' ');
+	char* s = rt.readfile("/tmp/zc-file-drop.txt");
+	rt.put_s(s); rt.put_c(' ');
+	rt.free(s);
+	std.File* g = std.Host.open("/tmp/zc-no-such-dir/x", 1);
+	rt.put_n(g == 0); rt.put_c(10);
+	return 0;
+}