Add test whether fflush() complies POSIX for the handling of

pushed-back wchar_t chars.

1 files changed, 82 insertions, 1 deletions

diff --git a/src/regress/lib/libc/stdio/test_fflush.c b/src/regress/lib/libc/stdio/test_fflush.c
index fe1772bdfc..76f2d88aba 100644
--- a/src/regress/lib/libc/stdio/test_fflush.c
+++ b/src/regress/lib/libc/stdio/test_fflush.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: test_fflush.c,v 1.1 2025/05/24 11:07:21 yasuoka Exp $ */
+/*      $OpenBSD: test_fflush.c,v 1.2 2025/05/25 05:35:13 yasuoka Exp $ */
 
 /*
  * Copyright (c) 2025 YASUOKA Masahiko <yasuoka@yasuoka.net>
@@ -17,10 +17,12 @@
  */
 
 #include <assert.h>
+#include <locale.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include <wchar.h>
 
 /* we use assert() */
 #undef  NDEBUG
@@ -34,6 +36,8 @@ void test_fflush_read1(void);
 void test_fflush_read2(void);
 void test_fflush_read3(void);
 void test_fflush_read4(void);
+void setupw(void);
+void test_fflush_read5(void);
 
 void
 setup(void)
@@ -212,14 +216,91 @@ test_fflush_read4(void)
         assert(r == 0);
 }
 
+void
+setupw(void)
+{
+        FILE    *fp;
+
+        /* common setup */
+        unlink(TMPFILENAME);
+        fp = fopen(TMPFILENAME, "w+");
+        assert(fp != NULL);
+        /* Konnitiwa Sekai(in Kanji) */
+        fputws(L"\u3053\u3093\u306b\u3061\u308f \u4e16\u754c\n", fp);
+        fclose(fp);
+}
+
+/* fflush work with reading file and seekable + ungetwc */
+void
+test_fflush_read5(void)
+{
+        int      r;
+        wchar_t  buf[80];
+        FILE    *fp;
+
+        setupw();
+
+        fp = fopen(TMPFILENAME, "r");
+
+        assert(fp != NULL);
+        assert(fgetwc(fp) == L'\u3053');        /* Ko */
+        assert(fgetwc(fp) == L'\u3093');        /* N  */
+        assert(fgetwc(fp) == L'\u306b');        /* Ni */
+        assert(fgetwc(fp) == L'\u3061');        /* Ti */
+        assert(fgetwc(fp) == L'\u308f');        /* Wa */
+
+        /* push 263A(smile) back */
+        assert(ungetwc(L'\u263a', fp));
+
+        /* we support 1 push back wchar_t */
+        assert(fgetwc(fp) == L'\u263a');
+
+        /* can read reset of that */
+        fgetws(buf, sizeof(buf), fp);
+        assert(wcscmp(buf, L" \u4e16\u754c\n") == 0);
+
+        r = fclose(fp);
+        assert(r == 0);
+
+        /* do the same thing + fflush */
+        fp = fopen(TMPFILENAME, "r");
+
+        assert(fp != NULL);
+        assert(fgetwc(fp) == L'\u3053');        /* Ko */
+        assert(fgetwc(fp) == L'\u3093');        /* N  */
+        assert(fgetwc(fp) == L'\u306b');        /* Ni */
+        assert(fgetwc(fp) == L'\u3061');        /* Ti */
+        assert(fgetwc(fp) == L'\u308f');        /* Wa */
+
+        /* push 263A(smile) back */
+        assert(ungetwc(L'\u263a', fp));
+
+        /* we support 1 push back wchar_t */
+        assert(fgetwc(fp) == L'\u263a');
+
+        /* then fflush */
+        r = fflush(fp);
+        assert(r == 0);
+
+        /* fllush() clears the all pushed back chars */
+
+        /* can read rest of that */
+        fgetws(buf, sizeof(buf), fp);
+        assert(wcscmp(buf, L" \u4e16\u754c\n") == 0);
+        r = fclose(fp);
+        assert(r == 0);
+}
 int
 main(int argc, char *argv[])
 {
+        setlocale(LC_ALL, "C.UTF-8");
+
         test_fflush_read0();
         test_fflush_read1();
         test_fflush_read2();
         test_fflush_read3();
         test_fflush_read4();
+        test_fflush_read5();
 
         exit(0);
 }