[libc-commits] [libc] [libc] implement fwide (PR #196157)
Michael Jones via libc-commits
libc-commits at lists.llvm.org
Thu May 7 10:54:20 PDT 2026
https://github.com/michaelrj-google updated https://github.com/llvm/llvm-project/pull/196157
>From 0af6f39e1069674be47231fc12da2c8087bd8ad3 Mon Sep 17 00:00:00 2001
From: Michael Jones <michaelrj at google.com>
Date: Wed, 6 May 2026 18:26:55 +0000
Subject: [PATCH 1/3] [libc] implement fwide
Add fwide function and tests. Part 1/11. All build file changes are in
part 11.
Assisted by Gemini
---
libc/src/wchar/fwide.cpp | 38 +++++++++++++++++++++
libc/src/wchar/fwide.h | 21 ++++++++++++
libc/test/src/wchar/fwide_test.cpp | 54 ++++++++++++++++++++++++++++++
3 files changed, 113 insertions(+)
create mode 100644 libc/src/wchar/fwide.cpp
create mode 100644 libc/src/wchar/fwide.h
create mode 100644 libc/test/src/wchar/fwide_test.cpp
diff --git a/libc/src/wchar/fwide.cpp b/libc/src/wchar/fwide.cpp
new file mode 100644
index 0000000000000..6965b4ea1ef82
--- /dev/null
+++ b/libc/src/wchar/fwide.cpp
@@ -0,0 +1,38 @@
+//===-- Implementation of fwide -------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/wchar/fwide.h"
+#include "hdr/types/FILE.h"
+#include "src/__support/File/file.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+#include "src/__support/macros/null_check.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, fwide, (::FILE *stream, int mode)) {
+ LIBC_CRASH_ON_NULLPTR(stream);
+ auto *f = reinterpret_cast<File *>(stream);
+
+ File::Orientation orient;
+ if (mode > 0) {
+ orient = f->try_set_orientation(File::Orientation::WIDE);
+ } else if (mode < 0) {
+ orient = f->try_set_orientation(File::Orientation::BYTE);
+ } else {
+ orient = f->get_orientation();
+ }
+
+ if (orient == File::Orientation::WIDE)
+ return 1;
+ if (orient == File::Orientation::BYTE)
+ return -1;
+ return 0;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/wchar/fwide.h b/libc/src/wchar/fwide.h
new file mode 100644
index 0000000000000..bdb5a0534ca77
--- /dev/null
+++ b/libc/src/wchar/fwide.h
@@ -0,0 +1,21 @@
+//===-- Implementation header for fwide -----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_WCHAR_FWIDE_H
+#define LLVM_LIBC_SRC_WCHAR_FWIDE_H
+
+#include "hdr/types/FILE.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int fwide(::FILE *stream, int mode);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_WCHAR_FWIDE_H
diff --git a/libc/test/src/wchar/fwide_test.cpp b/libc/test/src/wchar/fwide_test.cpp
new file mode 100644
index 0000000000000..6131310a13018
--- /dev/null
+++ b/libc/test/src/wchar/fwide_test.cpp
@@ -0,0 +1,54 @@
+//===-- Unittests for fwide -----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/stdio/fclose.h"
+#include "src/stdio/fopen.h"
+#include "src/wchar/fwide.h"
+#include "test/UnitTest/Test.h"
+
+TEST(LlvmLibcFwideTest, QueryInitial) {
+ auto FILENAME =
+ libc_make_test_file_path(APPEND_LIBC_TEST("fwide_query.test"));
+ ::FILE *file = LIBC_NAMESPACE::fopen(FILENAME, "w");
+ ASSERT_FALSE(file == nullptr);
+
+ // Initial orientation should be unoriented (0)
+ EXPECT_EQ(LIBC_NAMESPACE::fwide(file, 0), 0);
+
+ ASSERT_EQ(LIBC_NAMESPACE::fclose(file), 0);
+}
+
+TEST(LlvmLibcFwideTest, OrientWide) {
+ auto FILENAME = libc_make_test_file_path(APPEND_LIBC_TEST("fwide_wide.test"));
+ ::FILE *file = LIBC_NAMESPACE::fopen(FILENAME, "w");
+ ASSERT_FALSE(file == nullptr);
+
+ // Setting mode > 0 should return > 0 (wide oriented)
+ EXPECT_GT(LIBC_NAMESPACE::fwide(file, 1), 0);
+
+ // Subsequent orientation queries/attempts should still return > 0
+ EXPECT_GT(LIBC_NAMESPACE::fwide(file, 0), 0);
+ EXPECT_GT(LIBC_NAMESPACE::fwide(file, -1), 0);
+
+ ASSERT_EQ(LIBC_NAMESPACE::fclose(file), 0);
+}
+
+TEST(LlvmLibcFwideTest, OrientByte) {
+ auto FILENAME = libc_make_test_file_path(APPEND_LIBC_TEST("fwide_byte.test"));
+ ::FILE *file = LIBC_NAMESPACE::fopen(FILENAME, "w");
+ ASSERT_FALSE(file == nullptr);
+
+ // Setting mode < 0 should return < 0 (byte oriented)
+ EXPECT_LT(LIBC_NAMESPACE::fwide(file, -1), 0);
+
+ // Subsequent orientation queries/attempts should still return < 0
+ EXPECT_LT(LIBC_NAMESPACE::fwide(file, 0), 0);
+ EXPECT_LT(LIBC_NAMESPACE::fwide(file, 1), 0);
+
+ ASSERT_EQ(LIBC_NAMESPACE::fclose(file), 0);
+}
>From 8a9f5a568e6129128b5172e4af334402ed08ee0a Mon Sep 17 00:00:00 2001
From: Michael Jones <michaelrj at google.com>
Date: Wed, 6 May 2026 20:04:51 +0000
Subject: [PATCH 2/3] format
---
libc/src/wchar/fwide.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libc/src/wchar/fwide.cpp b/libc/src/wchar/fwide.cpp
index 6965b4ea1ef82..19af86e79de79 100644
--- a/libc/src/wchar/fwide.cpp
+++ b/libc/src/wchar/fwide.cpp
@@ -15,7 +15,7 @@
namespace LIBC_NAMESPACE_DECL {
-LLVM_LIBC_FUNCTION(int, fwide, (::FILE *stream, int mode)) {
+LLVM_LIBC_FUNCTION(int, fwide, (::FILE * stream, int mode)) {
LIBC_CRASH_ON_NULLPTR(stream);
auto *f = reinterpret_cast<File *>(stream);
>From ab5e539a24b6033c68c2e8afe98c6ecf5afe164c Mon Sep 17 00:00:00 2001
From: Michael Jones <michaelrj at google.com>
Date: Thu, 7 May 2026 17:53:24 +0000
Subject: [PATCH 3/3] fix header formatting, add build setup.
---
libc/config/linux/aarch64/entrypoints.txt | 12 ++
libc/config/linux/riscv/entrypoints.txt | 12 ++
libc/config/linux/x86_64/entrypoints.txt | 12 +-
libc/include/wchar.yaml | 67 +++++++++++
libc/src/wchar/CMakeLists.txt | 139 +++++++++++++++++++++-
libc/src/wchar/fwide.cpp | 8 +-
libc/src/wchar/fwide.h | 8 +-
7 files changed, 254 insertions(+), 4 deletions(-)
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index ea3f4cd8f51a0..a0fb4663c1e54 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -1242,6 +1242,18 @@ if(LLVM_LIBC_FULL_BUILD)
# sys/select.h entrypoints
libc.src.sys.select.select
+
+ # wchar.h entrypoints
+ # libc.src.wchar.fgetwc
+ # libc.src.wchar.fgetws
+ # libc.src.wchar.fputwc
+ # libc.src.wchar.fputws
+ libc.src.wchar.fwide
+ # libc.src.wchar.getwc
+ # libc.src.wchar.getwchar
+ # libc.src.wchar.putwc
+ # libc.src.wchar.putwchar
+ # libc.src.wchar.ungetwc
)
endif()
diff --git a/libc/config/linux/riscv/entrypoints.txt b/libc/config/linux/riscv/entrypoints.txt
index d8d520c6d4236..f67984d4f6484 100644
--- a/libc/config/linux/riscv/entrypoints.txt
+++ b/libc/config/linux/riscv/entrypoints.txt
@@ -1376,6 +1376,18 @@ if(LLVM_LIBC_FULL_BUILD)
# sys/select.h entrypoints
libc.src.sys.select.select
+
+ # wchar.h entrypoints
+ # libc.src.wchar.fgetwc
+ # libc.src.wchar.fgetws
+ # libc.src.wchar.fputwc
+ # libc.src.wchar.fputws
+ libc.src.wchar.fwide
+ # libc.src.wchar.getwc
+ # libc.src.wchar.getwchar
+ # libc.src.wchar.putwc
+ # libc.src.wchar.putwchar
+ # libc.src.wchar.ungetwc
)
endif()
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index dfd6064951d52..b6247c1172150 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -1463,9 +1463,19 @@ if(LLVM_LIBC_FULL_BUILD)
libc.src.wchar.wcrtomb
libc.src.wchar.wcsrtombs
libc.src.wchar.wcsnrtombs
+ # libc.src.wchar.fgetwc
+ # libc.src.wchar.fgetws
+ # libc.src.wchar.fputwc
+ # libc.src.wchar.fputws
+ libc.src.wchar.fwide
+ # libc.src.wchar.getwc
+ # libc.src.wchar.getwchar
+ # libc.src.wchar.putwc
+ # libc.src.wchar.putwchar
+ # libc.src.wchar.ungetwc
# nl_types.h entrypoints
- libc.src.nl_types.catopen
+ libc.src.nl_types.catopen
libc.src.nl_types.catclose
libc.src.nl_types.catgets
)
diff --git a/libc/include/wchar.yaml b/libc/include/wchar.yaml
index 6575f2504c900..c7a956d542ff6 100644
--- a/libc/include/wchar.yaml
+++ b/libc/include/wchar.yaml
@@ -369,3 +369,70 @@ functions:
- type: wchar_t *__restrict
- type: const wchar_t *__restrict
- type: size_t
+ - name: fgetwc
+ standards:
+ - stdc
+ return_type: wint_t
+ arguments:
+ - type: FILE *
+ - name: fgetws
+ standards:
+ - stdc
+ return_type: wchar_t *
+ arguments:
+ - type: wchar_t *__restrict
+ - type: int
+ - type: FILE *__restrict
+ - name: fputwc
+ standards:
+ - stdc
+ return_type: wint_t
+ arguments:
+ - type: wchar_t
+ - type: FILE *
+ - name: fputws
+ standards:
+ - stdc
+ return_type: int
+ arguments:
+ - type: const wchar_t *__restrict
+ - type: FILE *__restrict
+ - name: fwide
+ standards:
+ - stdc
+ return_type: int
+ arguments:
+ - type: FILE *
+ - type: int
+ - name: getwc
+ standards:
+ - stdc
+ return_type: wint_t
+ arguments:
+ - type: FILE *
+ - name: getwchar
+ standards:
+ - stdc
+ return_type: wint_t
+ arguments:
+ - type: void
+ - name: putwc
+ standards:
+ - stdc
+ return_type: wint_t
+ arguments:
+ - type: wchar_t
+ - type: FILE *
+ - name: putwchar
+ standards:
+ - stdc
+ return_type: wint_t
+ arguments:
+ - type: wchar_t
+ - name: ungetwc
+ standards:
+ - stdc
+ return_type: wint_t
+ arguments:
+ - type: wint_t
+ - type: FILE *
diff --git a/libc/src/wchar/CMakeLists.txt b/libc/src/wchar/CMakeLists.txt
index 89383c33c6a4e..6b075da6d430c 100644
--- a/libc/src/wchar/CMakeLists.txt
+++ b/libc/src/wchar/CMakeLists.txt
@@ -310,7 +310,7 @@ add_entrypoint_object(
libc.hdr.types.size_t
libc.hdr.wchar_macros
libc.src.__support.macros.null_check
-)
+)
add_entrypoint_object(
wcschr
@@ -566,3 +566,140 @@ add_entrypoint_object(
libc.src.__support.macros.config
libc.src.__support.common
)
+
+add_entrypoint_object(
+ fwide
+ SRCS
+ fwide.cpp
+ HDRS
+ fwide.h
+ DEPENDS
+ libc.hdr.types.FILE
+ libc.src.__support.File.file
+ libc.src.__support.macros.null_check
+)
+
+add_entrypoint_object(
+ fputwc
+ SRCS
+ fputwc.cpp
+ HDRS
+ fputwc.h
+ DEPENDS
+ libc.hdr.types.FILE
+ libc.hdr.types.wint_t
+ libc.hdr.types.wchar_t
+ libc.hdr.wchar_macros
+ libc.src.__support.File.file
+ libc.src.__support.libc_errno
+ libc.src.__support.macros.null_check
+)
+
+add_entrypoint_object(
+ fgetwc
+ SRCS
+ fgetwc.cpp
+ HDRS
+ fgetwc.h
+ DEPENDS
+ libc.hdr.types.FILE
+ libc.hdr.types.wint_t
+ libc.hdr.types.wchar_t
+ libc.src.__support.File.file
+ libc.src.__support.libc_errno
+ libc.src.__support.macros.null_check
+)
+
+add_entrypoint_object(
+ fputws
+ SRCS
+ fputws.cpp
+ HDRS
+ fputws.h
+ DEPENDS
+ libc.hdr.types.FILE
+ libc.hdr.types.wchar_t
+ libc.src.__support.File.file
+ libc.src.__support.libc_errno
+ libc.src.string.string_utils
+ libc.src.__support.macros.null_check
+)
+
+add_entrypoint_object(
+ fgetws
+ SRCS
+ fgetws.cpp
+ HDRS
+ fgetws.h
+ DEPENDS
+ libc.hdr.types.FILE
+ libc.hdr.types.wchar_t
+ libc.src.__support.File.file
+ libc.src.__support.libc_errno
+ libc.src.__support.macros.null_check
+)
+
+add_entrypoint_object(
+ ungetwc
+ SRCS
+ ungetwc.cpp
+ HDRS
+ ungetwc.h
+ DEPENDS
+ libc.hdr.types.FILE
+ libc.hdr.types.wint_t
+ libc.src.__support.File.file
+ libc.src.__support.macros.null_check
+)
+
+add_entrypoint_object(
+ getwc
+ SRCS
+ getwc.cpp
+ HDRS
+ getwc.h
+ DEPENDS
+ libc.hdr.types.FILE
+ libc.hdr.types.wint_t
+ libc.src.__support.File.file
+ libc.src.__support.libc_errno
+ libc.src.__support.macros.null_check
+)
+
+add_entrypoint_object(
+ getwchar
+ SRCS
+ getwchar.cpp
+ HDRS
+ getwchar.h
+ DEPENDS
+ libc.src.stdio.stdin
+ libc.src.__support.File.file
+ libc.src.__support.libc_errno
+)
+
+add_entrypoint_object(
+ putwc
+ SRCS
+ putwc.cpp
+ HDRS
+ putwc.h
+ DEPENDS
+ libc.hdr.types.FILE
+ libc.hdr.types.wint_t
+ libc.src.__support.File.file
+ libc.src.__support.libc_errno
+ libc.src.__support.macros.null_check
+)
+
+add_entrypoint_object(
+ putwchar
+ SRCS
+ putwchar.cpp
+ HDRS
+ putwchar.h
+ DEPENDS
+ libc.src.stdio.stdout
+ libc.src.__support.File.file
+ libc.src.__support.libc_errno
+)
diff --git a/libc/src/wchar/fwide.cpp b/libc/src/wchar/fwide.cpp
index 19af86e79de79..ada4c30ba9c59 100644
--- a/libc/src/wchar/fwide.cpp
+++ b/libc/src/wchar/fwide.cpp
@@ -1,10 +1,16 @@
-//===-- Implementation of fwide -------------------------------------------===//
+//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains the implementation of the fwide function, which sets and
+/// gets the orientation of a stream.
+///
+//===----------------------------------------------------------------------===//
#include "src/wchar/fwide.h"
#include "hdr/types/FILE.h"
diff --git a/libc/src/wchar/fwide.h b/libc/src/wchar/fwide.h
index bdb5a0534ca77..1463af6db9604 100644
--- a/libc/src/wchar/fwide.h
+++ b/libc/src/wchar/fwide.h
@@ -1,10 +1,16 @@
-//===-- Implementation header for fwide -----------------------------------===//
+//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains the prototype of the fwide function, which sets and
+/// gets the orientation of a stream.
+///
+//===----------------------------------------------------------------------===//
#ifndef LLVM_LIBC_SRC_WCHAR_FWIDE_H
#define LLVM_LIBC_SRC_WCHAR_FWIDE_H
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