vasnwprintf-posix: Fix behaviour in the C locale.

* lib/vasnprintf.c (VASNPRINTF): If NEED_WPRINTF_DIRECTIVE_C is set,
implement the 'c' directive here.
* m4/vasnprintf.m4 (gl_PREREQ_VASNWPRINTF): Invoke gl_MBRTOWC_C_LOCALE.
If mbrtowc is buggy in the C locale, define NEED_WPRINTF_DIRECTIVE_C.
* modules/vasnwprintf (Files): Add m4/mbrtowc.m4.
* tests/test-vasnwprintf-posix.c (test_function): Add tests of %s and %c
in the C locale.
* doc/posix-functions/fwprintf.texi: Mention the C locale behaviour bug.
* doc/posix-functions/swprintf.texi: Likewise.
* doc/posix-functions/vfwprintf.texi: Likewise.
* doc/posix-functions/vswprintf.texi: Likewise.
* doc/posix-functions/vwprintf.texi: Likewise.
* doc/posix-functions/wprintf.texi: Likewise.

6 files changed, 24 insertions, 0 deletions

diff --git a/doc/posix-functions/fwprintf.texi b/doc/posix-functions/fwprintf.texi
index 2b4600de11..db42363cfa 100644
--- a/doc/posix-functions/fwprintf.texi
+++ b/doc/posix-functions/fwprintf.texi
@@ -34,6 +34,10 @@ The @code{%m} directive is not portable, use @code{%s} mapped to an
 argument of @code{strerror(errno)} (or a version of @code{strerror_r})
 instead.
 @item
+In the C or POSIX locales, the @code{%c} and @code{%s} conversions may fail
+on some platforms:
+glibc 2.35.
+@item
 When formatting an integer with grouping flag, this function inserts thousands
 separators even in the "C" locale on some platforms:
 NetBSD 5.1.
diff --git a/doc/posix-functions/swprintf.texi b/doc/posix-functions/swprintf.texi
index b53c96c6d7..cd20d0e702 100644
--- a/doc/posix-functions/swprintf.texi
+++ b/doc/posix-functions/swprintf.texi
@@ -63,6 +63,10 @@ The @code{%m} directive is not portable, use @code{%s} mapped to an
 argument of @code{strerror(errno)} (or a version of @code{strerror_r})
 instead.
 @item
+In the C or POSIX locales, the @code{%c} and @code{%s} conversions may fail
+on some platforms:
+glibc 2.35.
+@item
 When formatting an integer with grouping flag, this function inserts thousands
 separators even in the "C" locale on some platforms:
 NetBSD 5.1.
diff --git a/doc/posix-functions/vfwprintf.texi b/doc/posix-functions/vfwprintf.texi
index 22e4a59212..0712269aa4 100644
--- a/doc/posix-functions/vfwprintf.texi
+++ b/doc/posix-functions/vfwprintf.texi
@@ -34,6 +34,10 @@ The @code{%m} directive is not portable, use @code{%s} mapped to an
 argument of @code{strerror(errno)} (or a version of @code{strerror_r})
 instead.
 @item
+In the C or POSIX locales, the @code{%c} and @code{%s} conversions may fail
+on some platforms:
+glibc 2.35.
+@item
 When formatting an integer with grouping flag, this function inserts thousands
 separators even in the "C" locale on some platforms:
 NetBSD 5.1.
diff --git a/doc/posix-functions/vswprintf.texi b/doc/posix-functions/vswprintf.texi
index 4083cfd2a1..7512a2d023 100644
--- a/doc/posix-functions/vswprintf.texi
+++ b/doc/posix-functions/vswprintf.texi
@@ -36,6 +36,10 @@ The @code{%m} directive is not portable, use @code{%s} mapped to an
 argument of @code{strerror(errno)} (or a version of @code{strerror_r})
 instead.
 @item
+In the C or POSIX locales, the @code{%c} and @code{%s} conversions may fail
+on some platforms:
+glibc 2.35.
+@item
 When formatting an integer with grouping flag, this function inserts thousands
 separators even in the "C" locale on some platforms:
 NetBSD 5.1.
diff --git a/doc/posix-functions/vwprintf.texi b/doc/posix-functions/vwprintf.texi
index 7b029c9ceb..1e364288f6 100644
--- a/doc/posix-functions/vwprintf.texi
+++ b/doc/posix-functions/vwprintf.texi
@@ -37,6 +37,10 @@ The @code{%m} directive is not portable, use @code{%s} mapped to an
 argument of @code{strerror(errno)} (or a version of @code{strerror_r})
 instead.
 @item
+In the C or POSIX locales, the @code{%c} and @code{%s} conversions may fail
+on some platforms:
+glibc 2.35.
+@item
 When formatting an integer with grouping flag, this function inserts thousands
 separators even in the "C" locale on some platforms:
 NetBSD 5.1.
diff --git a/doc/posix-functions/wprintf.texi b/doc/posix-functions/wprintf.texi
index 56106b309e..c4d58fab2e 100644
--- a/doc/posix-functions/wprintf.texi
+++ b/doc/posix-functions/wprintf.texi
@@ -37,6 +37,10 @@ The @code{%m} directive is not portable, use @code{%s} mapped to an
 argument of @code{strerror(errno)} (or a version of @code{strerror_r})
 instead.
 @item
+In the C or POSIX locales, the @code{%c} and @code{%s} conversions may fail
+on some platforms:
+glibc 2.35.
+@item
 When formatting an integer with grouping flag, this function inserts thousands
 separators even in the "C" locale on some platforms:
 NetBSD 5.1.