* [PATCH] libstdc++: Fix build failure due to missing <langinfo.h> [PR98374]
@ 2020-12-18 16:04 Patrick Palka
2020-12-18 17:16 ` Patrick Palka
0 siblings, 1 reply; 2+ messages in thread
From: Patrick Palka @ 2020-12-18 16:04 UTC (permalink / raw)
To: gcc-patches; +Cc: libstdc++, Patrick Palka
This fixes a build failure on Windows which lacks <langinfo.h>.
(We can't use the more portable localeconv() from <clocale> to obtain
the radix character of the current locale here because it's not
thread-safe, unfortunately.)
This change means that on Windows and other such systems, we'll just
always assume the radix character used by printf is '.' when formatting
a long double through it.
libstdc++-v3/ChangeLog:
PR libstdc++/98374
* src/c++17/floating_to_chars.cc: Guard include of <langinfo.h>
with __has_include.
(__floating_to_chars_precision) [!defined(RADIXCHAR)]: Don't
attempt to obtain the radix character of the current locale,
just assume it's '.'.
---
libstdc++-v3/src/c++17/floating_to_chars.cc | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/libstdc++-v3/src/c++17/floating_to_chars.cc b/libstdc++-v3/src/c++17/floating_to_chars.cc
index 474e791e717..6470fbb0b95 100644
--- a/libstdc++-v3/src/c++17/floating_to_chars.cc
+++ b/libstdc++-v3/src/c++17/floating_to_chars.cc
@@ -33,7 +33,9 @@
#include <cmath>
#include <cstdio>
#include <cstring>
-#include <langinfo.h>
+#if __has_include(<langinfo.h>)
+# include <langinfo.h> // for nl_langinfo
+#endif
#include <optional>
#include <string_view>
#include <type_traits>
@@ -1113,6 +1115,7 @@ template<typename T>
// to handle a radix point that's different from '.'.
char radix[6] = {'.', '\0', '\0', '\0', '\0', '\0'};
if (effective_precision > 0)
+#ifdef RADIXCHAR
// ???: Can nl_langinfo() ever return null?
if (const char* const radix_ptr = nl_langinfo(RADIXCHAR))
{
@@ -1121,6 +1124,7 @@ template<typename T>
// UTF-8 character) wide.
__glibcxx_assert(radix[4] == '\0');
}
+#endif
// Compute straightforward upper bounds on the output length.
int output_length_upper_bound;
--
2.30.0.rc0
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] libstdc++: Fix build failure due to missing <langinfo.h> [PR98374]
2020-12-18 16:04 [PATCH] libstdc++: Fix build failure due to missing <langinfo.h> [PR98374] Patrick Palka
@ 2020-12-18 17:16 ` Patrick Palka
0 siblings, 0 replies; 2+ messages in thread
From: Patrick Palka @ 2020-12-18 17:16 UTC (permalink / raw)
To: GCC Patches; +Cc: Jonathan Wakely via Libstdc++
On Fri, Dec 18, 2020 at 11:04 AM Patrick Palka <ppalka@redhat.com> wrote:
>
> This fixes a build failure on Windows which lacks <langinfo.h>.
> (We can't use the more portable localeconv() from <clocale> to obtain
> the radix character of the current locale here because it's not
> thread-safe, unfortunately.)
>
> This change means that on Windows and other such systems, we'll just
> always assume the radix character used by printf is '.' when formatting
> a long double through it.
>
> libstdc++-v3/ChangeLog:
>
> PR libstdc++/98374
> * src/c++17/floating_to_chars.cc: Guard include of <langinfo.h>
> with __has_include.
> (__floating_to_chars_precision) [!defined(RADIXCHAR)]: Don't
> attempt to obtain the radix character of the current locale,
> just assume it's '.'.
I went ahead and committed this patch under the "obvious" rule as r11-6259.
> ---
> libstdc++-v3/src/c++17/floating_to_chars.cc | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/libstdc++-v3/src/c++17/floating_to_chars.cc b/libstdc++-v3/src/c++17/floating_to_chars.cc
> index 474e791e717..6470fbb0b95 100644
> --- a/libstdc++-v3/src/c++17/floating_to_chars.cc
> +++ b/libstdc++-v3/src/c++17/floating_to_chars.cc
> @@ -33,7 +33,9 @@
> #include <cmath>
> #include <cstdio>
> #include <cstring>
> -#include <langinfo.h>
> +#if __has_include(<langinfo.h>)
> +# include <langinfo.h> // for nl_langinfo
> +#endif
> #include <optional>
> #include <string_view>
> #include <type_traits>
> @@ -1113,6 +1115,7 @@ template<typename T>
> // to handle a radix point that's different from '.'.
> char radix[6] = {'.', '\0', '\0', '\0', '\0', '\0'};
> if (effective_precision > 0)
> +#ifdef RADIXCHAR
> // ???: Can nl_langinfo() ever return null?
> if (const char* const radix_ptr = nl_langinfo(RADIXCHAR))
> {
> @@ -1121,6 +1124,7 @@ template<typename T>
> // UTF-8 character) wide.
> __glibcxx_assert(radix[4] == '\0');
> }
> +#endif
>
> // Compute straightforward upper bounds on the output length.
> int output_length_upper_bound;
> --
> 2.30.0.rc0
>
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