stdio-common: Add tests for formatted dprintf output specifiers

Wire dprintf into test infrastructure for formatted printf output
specifiers.

Reviewed-by: DJ Delorie <dj@redhat.com>

1 files changed, 58 insertions, 0 deletions

diff --git a/stdio-common/tst-printf-format-d.h b/stdio-common/tst-printf-format-d.h
new file mode 100644
index 0000000..af7f26c
--- /dev/null
+++ b/stdio-common/tst-printf-format-d.h
@@ -0,0 +1,58 @@
+/* Test feature wrapper for formatted 'dprintf' output.
+   Copyright (C) 2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+
+/* We need to go through the POSIX-mandated dance to switch between
+   handles on an open file description.  */
+
+#define printf_under_test(...)						\
+({									\
+  __label__ out;							\
+  int result;								\
+									\
+  result = fflush (stdout);						\
+  if (result == EOF)							\
+    {									\
+      perror ("fflush");						\
+      goto out;								\
+    }									\
+  result = lseek (STDOUT_FILENO, 0, SEEK_END);				\
+  if (result < 0 && errno == ESPIPE)					\
+    result = 0;								\
+  if (result < 0)							\
+    {									\
+      perror ("lseek");							\
+      goto out;								\
+    }									\
+  result = dprintf (STDOUT_FILENO, __VA_ARGS__);			\
+  if (result < 0)							\
+    {									\
+      perror ("dprintf");						\
+      goto out;								\
+    }									\
+  result = fseek (stdout, 0, SEEK_END);					\
+  if (result < 0 && errno == ESPIPE)					\
+    result = 0;								\
+  if (result < 0)							\
+    perror ("fseek");							\
+out:									\
+  result;								\
+})