--- /dev/null
+++ Libc/Libc-1725.0.11/tests/stdio.c
@@ -0,0 +1,134 @@
+#include <stdio.h>
+#include <err.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/resource.h>
+#include <stdlib.h>
+#include <sys/sysctl.h>
+
+#include <darwintest.h>
+
+#define FILE_LIMIT 15
+
+/*
+ * Validate the maximum number of fds allowed open per process
+ * implemented by the kernel matches what sysconf expects:
+ *  32 bit: OPEN_MAX
+ *  64 bit: RLIM_INFINITY
+ */
+T_DECL(stdio_PR_63187147_SC_STREAM_MAX, "_SC_STREAM_MAX test")
+{
+	struct rlimit rlim;
+	long stream_max, saved_stream_max;
+	int maxfilesperproc, err;
+	size_t maxfilesperproc_size = sizeof(maxfilesperproc);
+
+	T_SETUPBEGIN;
+
+	saved_stream_max = sysconf(_SC_STREAM_MAX);
+	T_LOG("Initial stream_max %ld", saved_stream_max);
+
+	/*
+	 * Determine the maximum number of fds allowed by the kernel
+	 */
+	err = sysctlbyname("kern.maxfilesperproc", &maxfilesperproc, &maxfilesperproc_size, NULL, 0);
+	T_EXPECT_POSIX_SUCCESS(err, "sysctlbyname(\"kern.maxfilesperproc\") returned %d", err);
+	T_LOG("kern.maxfilesperproc %d", maxfilesperproc);
+
+	/*
+	 * Raise RLIMIT_NOFILE to RLIM_INFINITY
+	 */
+	err = getrlimit(RLIMIT_NOFILE, &rlim);
+	T_EXPECT_POSIX_SUCCESS(err, "getrlimit(RLIMIT_NOFILE)");
+	T_LOG("Initial RLIMIT_NOFILE rlim.cur: 0x%llx", rlim.rlim_cur);
+	rlim.rlim_cur = RLIM_INFINITY;
+	err = setrlimit(RLIMIT_NOFILE, &rlim);
+	T_EXPECT_POSIX_SUCCESS(err, "setrlimit(RLIMIT_NOFILE) to RLIM_INFINITY");
+	err = getrlimit(RLIMIT_NOFILE, &rlim);
+	T_EXPECT_POSIX_SUCCESS(err, "New RLIMIT_NOFILE rlim_cur: 0x%llx", rlim.rlim_cur);
+
+	T_SETUPEND;
+
+	/*
+	 * The largest value sysconf returns for _SC_STREAM_MAX is
+	 * OPEN_MAX (32 bit) or RLIM_INFINITY (64 bit)
+	 */
+	stream_max = sysconf(_SC_STREAM_MAX);
+	T_EXPECT_NE_LONG((long)-1, stream_max, "stream_max %ld", stream_max);
+#if __LP64__
+	T_EXPECT_EQ((long)RLIM_INFINITY, stream_max, "sysconf returned 0x%lx", stream_max);
+#else
+	T_EXPECT_EQ((long)OPEN_MAX, stream_max, "sysconf returned 0x%lx", stream_max);
+#endif
+}
+
+/*
+ * Verify that a) {STREAM_MAX} reflects RLIMIT_NOFILE, b) we cannot open
+ * more than {STREAM_MAX} streams (taking into account the pre-existing
+ * stdin, stdout, stderr) and c) raising RLIMIT_NOFILE after hitting the
+ * limit immediately lets us open additional streams up to the new limit.
+ */
+T_DECL(stdio_PR_22813396, "STREAM_MAX is affected by changes to RLIMIT_NOFILE")
+{
+	struct rlimit rlim;
+	long i, stream_max;
+	FILE *f;
+
+	T_SETUPBEGIN;
+	T_ASSERT_POSIX_NOTNULL(f = fdopen(dup(0), "r"), "opening initial stream");
+	T_ASSERT_POSIX_ZERO(getrlimit(RLIMIT_NOFILE, &rlim), "getting file limit");
+	T_ASSERT_POSIX_SUCCESS(stream_max = sysconf(_SC_STREAM_MAX),
+	    "getting stream limit");
+	T_ASSERT_EQ_ULLONG((unsigned long long)stream_max, rlim.rlim_cur,
+	    "stream limit equals file limit");
+	rlim.rlim_cur = FILE_LIMIT;
+	T_ASSERT_POSIX_ZERO(setrlimit(RLIMIT_NOFILE, &rlim), "setting file limit");
+	T_ASSERT_POSIX_SUCCESS(stream_max = sysconf(_SC_STREAM_MAX),
+	    "refreshing stream limit");
+	T_ASSERT_EQ_LONG(stream_max, (long)FILE_LIMIT,
+	    "stream limit equals file limit");
+	T_SETUPEND;
+	for (i = 4; i < stream_max; i++)
+		T_EXPECT_POSIX_NOTNULL(fdopen(0, "r"), "opening stream within limit");
+	T_EXPECT_NULL(fdopen(0, "r"), "opening stream beyond limit");
+	T_SETUPBEGIN;
+	rlim.rlim_cur = FILE_LIMIT + 1;
+	T_ASSERT_POSIX_ZERO(setrlimit(RLIMIT_NOFILE, &rlim), "raising file limit");
+	T_SETUPEND;
+	T_EXPECT_POSIX_NOTNULL(fdopen(0, "r"), "opening stream after raising limit");
+	T_EXPECT_NULL(fdopen(0, "r"), "opening stream beyond raised limit");
+}
+
+/*
+ * Verify that a) {STREAM_MAX} reflects RLIMIT_NOFILE, b) we cannot open
+ * more than {STREAM_MAX} streams (taking into account the pre-existing
+ * stdin, stdout, stderr) and c) closing a stream after hitting the limit
+ * immediately lets us open exactly one other.
+ */
+T_DECL(stdio_PR_22813396_close, "STREAM_MAX is enforced properly after fclose")
+{
+	struct rlimit rlim;
+	long i, stream_max;
+	FILE *f;
+
+	T_SETUPBEGIN;
+	T_ASSERT_POSIX_NOTNULL(f = fdopen(dup(0), "r"), "opening initial stream");
+	T_ASSERT_POSIX_ZERO(getrlimit(RLIMIT_NOFILE, &rlim), "getting file limit");
+	T_ASSERT_POSIX_SUCCESS(stream_max = sysconf(_SC_STREAM_MAX),
+	    "getting stream limit");
+	T_ASSERT_EQ_ULLONG((unsigned long long)stream_max, rlim.rlim_cur,
+	    "stream limit equals file limit");
+	rlim.rlim_cur = FILE_LIMIT;
+	T_ASSERT_POSIX_ZERO(setrlimit(RLIMIT_NOFILE, &rlim), "setting file limit");
+	T_ASSERT_POSIX_SUCCESS(stream_max = sysconf(_SC_STREAM_MAX),
+	    "refreshing stream limit");
+	T_ASSERT_EQ_LONG(stream_max, (long)FILE_LIMIT,
+	    "stream limit equals file limit");
+	T_SETUPEND;
+	for (i = 4; i < stream_max; i++)
+		T_EXPECT_POSIX_NOTNULL(fdopen(0, "r"), "opening stream within limit");
+	T_EXPECT_NULL(fdopen(0, "r"), "opening stream beyond limit");
+	T_EXPECT_POSIX_ZERO(fclose(f), "closing a stream");
+	T_EXPECT_POSIX_NOTNULL(fdopen(0, "r"), "opening stream after closing another");
+	T_EXPECT_NULL(fdopen(0, "r"), "opening second stream after closing only one");
+}