[libc] add wctype.h header (#149202)

Prabhuk · web-flow · commit e8182fb50162 · 2025-07-17T13:06:04.000-07:00
Add basic configurations to generate wctype.h header file. To begin with
this header file just exposes one function iswalpha.
diff --git a/libc/config/baremetal/arm/entrypoints.txt b/libc/config/baremetal/arm/entrypoints.txt
@@ -278,6 +278,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.wchar.wcslen
     libc.src.wchar.wctob
 
+    # wctype.h entrypoints
+    libc.src.wctype.iswalpha
+
     # internal entrypoints
     libc.startup.baremetal.init
     libc.startup.baremetal.fini
diff --git a/libc/config/baremetal/arm/headers.txt b/libc/config/baremetal/arm/headers.txt
@@ -23,4 +23,5 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.time
     libc.include.uchar
     libc.include.wchar
+    libc.include.wctype
 )
diff --git a/libc/config/baremetal/riscv/entrypoints.txt b/libc/config/baremetal/riscv/entrypoints.txt
@@ -278,6 +278,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.wchar.wcslen
     libc.src.wchar.wctob
 
+    # wctype.h entrypoints
+    libc.src.wctype.iswalpha
+
     # internal entrypoints
     libc.startup.baremetal.init
     libc.startup.baremetal.fini
diff --git a/libc/config/baremetal/riscv/headers.txt b/libc/config/baremetal/riscv/headers.txt
@@ -23,4 +23,5 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.time
     libc.include.uchar
     libc.include.wchar
+    libc.include.wctype
 )
diff --git a/libc/config/darwin/aarch64/entrypoints.txt b/libc/config/darwin/aarch64/entrypoints.txt
@@ -99,6 +99,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdlib.calloc
     libc.src.stdlib.realloc
     libc.src.stdlib.free
+
+    # wctype.h entrypoints
+    libc.src.wctype.iswalpha
 )
 
 if(LLVM_LIBC_FULL_BUILD)
diff --git a/libc/config/darwin/aarch64/headers.txt b/libc/config/darwin/aarch64/headers.txt
@@ -11,4 +11,5 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.stdlib
     libc.include.string
     libc.include.strings
+    libc.include.wctype
 )
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
@@ -363,6 +363,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.wchar.wcslen
     libc.src.wchar.wctob
 
+    # wctype.h entrypoints
+    libc.src.wctype.iswalpha
+
     # sys/uio.h entrypoints
     libc.src.sys.uio.writev
     libc.src.sys.uio.readv
diff --git a/libc/config/linux/aarch64/headers.txt b/libc/config/linux/aarch64/headers.txt
@@ -57,4 +57,5 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.uchar
     libc.include.unistd
     libc.include.wchar
+    libc.include.wctype
 )
diff --git a/libc/config/linux/arm/entrypoints.txt b/libc/config/linux/arm/entrypoints.txt
@@ -191,6 +191,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     # sys/time.h entrypoints
     libc.src.sys.time.setitimer
     libc.src.sys.time.getitimer
+
+    # wctype.h entrypoints
+    libc.src.wctype.iswalpha
 )
 
 if(LLVM_LIBC_FULL_BUILD)
diff --git a/libc/config/linux/arm/headers.txt b/libc/config/linux/arm/headers.txt
@@ -17,6 +17,7 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.strings
     libc.include.uchar
     libc.include.wchar
+    libc.include.wctype
 
     # Disabled due to epoll_wait syscalls not being available on this platform.
     # libc.include.sys_epoll
diff --git a/libc/config/linux/riscv/entrypoints.txt b/libc/config/linux/riscv/entrypoints.txt
@@ -368,6 +368,9 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.wchar.wcslen
     libc.src.wchar.wctob
 
+    # wctype.h entrypoints
+    libc.src.wctype.iswalpha
+
     # sys/uio.h entrypoints
     libc.src.sys.uio.writev
     libc.src.sys.uio.readv
diff --git a/libc/config/linux/riscv/headers.txt b/libc/config/linux/riscv/headers.txt
@@ -57,4 +57,5 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.uchar
     libc.include.unistd
     libc.include.wchar
+    libc.include.wctype
 )
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
@@ -396,6 +396,8 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.wchar.wcstoul
     libc.src.wchar.wcstoull
 
+    # wctype.h entrypoints
+    libc.src.wctype.iswalpha
 
     # sys/uio.h entrypoints
     libc.src.sys.uio.writev
diff --git a/libc/config/linux/x86_64/headers.txt b/libc/config/linux/x86_64/headers.txt
@@ -57,4 +57,5 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.uchar
     libc.include.unistd
     libc.include.wchar
+    libc.include.wctype
 )
diff --git a/libc/config/windows/entrypoints.txt b/libc/config/windows/entrypoints.txt
@@ -105,6 +105,9 @@ set(TARGET_LIBC_ENTRYPOINTS
 
     # unistd.h entrypoints
     libc.src.unistd.getentropy
+
+    # wctype.h entrypoints
+    libc.src.wctype.iswalpha
 )
 
 set(TARGET_LIBM_ENTRYPOINTS
diff --git a/libc/config/windows/headers.txt b/libc/config/windows/headers.txt
@@ -7,4 +7,5 @@ set(TARGET_PUBLIC_HEADERS
     libc.include.fenv
     libc.include.math
     libc.include.unistd
+    libc.include.wctype
 )
diff --git a/libc/include/CMakeLists.txt b/libc/include/CMakeLists.txt
@@ -720,6 +720,15 @@ add_header_macro(
     .llvm-libc-types.wchar_t
 )
 
+add_header_macro(
+  wctype
+  ../libc/include/wctype.yaml
+  wctype.h
+  DEPENDS
+    .llvm_libc_common_h    
+    .llvm-libc-types.wint_t
+)
+
 add_header_macro(
   locale
   ../libc/include/locale.yaml
diff --git a/libc/include/wctype.yaml b/libc/include/wctype.yaml
@@ -0,0 +1,10 @@
+header: wctype.h
+types:
+  - type_name: wint_t
+functions:
+  - name: iswalpha
+    standards:
+      - stdc
+    return_type: int
+    arguments:
+      - type: wint_t
diff --git a/libc/src/CMakeLists.txt b/libc/src/CMakeLists.txt
@@ -17,6 +17,7 @@ add_subdirectory(strings)
 add_subdirectory(time)
 add_subdirectory(unistd)
 add_subdirectory(wchar)
+add_subdirectory(wctype)
 
 if(${LIBC_TARGET_OS} STREQUAL "linux")
   add_subdirectory(dirent)
diff --git a/libc/src/wctype/CMakeLists.txt b/libc/src/wctype/CMakeLists.txt
@@ -0,0 +1,9 @@
+add_entrypoint_object(
+  iswalpha
+  SRCS
+    iswalpha.cpp
+  HDRS
+    iswalpha.h
+  DEPENDS
+    libc.src.__support.wctype_utils    
+)
diff --git a/libc/src/wctype/iswalpha.cpp b/libc/src/wctype/iswalpha.cpp
@@ -0,0 +1,19 @@
+//===-- Implementation of iswalpha ----------------------------------------===//
+//
+// 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/wctype/iswalpha.h"
+#include "src/__support/common.h"
+#include "src/__support/wctype_utils.h"
+
+#include "hdr/types/wint_t.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(bool, iswalpha, (wint_t c)) { return internal::iswalpha(c); }
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/wctype/iswalpha.h b/libc/src/wctype/iswalpha.h
@@ -0,0 +1,21 @@
+//===-- Implementation header for iswalpha ----------------------*- C++ -*-===//
+//
+// 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_WCTYPE_ISWALPHA_H
+#define LLVM_LIBC_SRC_WCTYPE_ISWALPHA_H
+
+#include "hdr/types/wint_t.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+bool iswalpha(wint_t c);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_WCTYPE_ISWALPHA_H
diff --git a/libc/test/src/CMakeLists.txt b/libc/test/src/CMakeLists.txt
@@ -70,6 +70,7 @@ add_subdirectory(stdlib)
 add_subdirectory(string)
 add_subdirectory(strings)
 add_subdirectory(wchar)
+add_subdirectory(wctype)
 add_subdirectory(time)
 add_subdirectory(unistd)
 
diff --git a/libc/test/src/wctype/CMakeLists.txt b/libc/test/src/wctype/CMakeLists.txt
@@ -0,0 +1,11 @@
+add_custom_target(libc_wctype_unittests)
+
+add_libc_test(
+  iswalpha_test
+  SUITE
+    libc_wctype_unittests
+  SRCS
+    iswalpha_test.cpp
+  DEPENDS
+    libc.src.wctype.iswalpha
+)
diff --git a/libc/test/src/wctype/iswalpha_test.cpp b/libc/test/src/wctype/iswalpha_test.cpp
@@ -0,0 +1,54 @@
+//===-- Unittests for iswalpha --------------------------------------------===//
+//
+// 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/__support/CPP/span.h"
+#include "src/wctype/iswalpha.h"
+
+#include "test/UnitTest/LibcTest.h"
+#include "test/UnitTest/Test.h"
+
+namespace {
+
+// TODO: Merge the wctype tests using this framework.
+constexpr char WALPHA_ARRAY[] = {
+    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
+    'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
+    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
+    'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
+};
+
+bool in_span(int ch, LIBC_NAMESPACE::cpp::span<const char> arr) {
+  for (size_t i = 0; i < arr.size(); ++i)
+    if (static_cast<int>(arr[i]) == ch)
+      return true;
+  return false;
+}
+
+} // namespace
+
+TEST(LlvmLibciswalpha, SimpleTest) {
+  EXPECT_TRUE(LIBC_NAMESPACE::iswalpha('a'));
+  EXPECT_TRUE(LIBC_NAMESPACE::iswalpha('B'));
+
+  EXPECT_FALSE(LIBC_NAMESPACE::iswalpha('3'));
+  EXPECT_FALSE(LIBC_NAMESPACE::iswalpha(' '));
+  EXPECT_FALSE(LIBC_NAMESPACE::iswalpha('?'));
+  EXPECT_FALSE(LIBC_NAMESPACE::iswalpha('\0'));
+  EXPECT_FALSE(LIBC_NAMESPACE::iswalpha(-1));
+}
+
+TEST(LlvmLibciswalpha, DefaultLocale) {
+  // Loops through all characters, verifying that letters return
+  // true and everything else returns false.
+  for (int ch = -255; ch < 255; ++ch) {
+    if (in_span(ch, WALPHA_ARRAY))
+      EXPECT_TRUE(LIBC_NAMESPACE::iswalpha(ch));
+    else
+      EXPECT_FALSE(LIBC_NAMESPACE::iswalpha(ch));
+  }
+}

Original file line number	Diff line number	Diff line change
`@@ -23,4 +23,5 @@ set(TARGET_PUBLIC_HEADERS`
`23`	`23`	`libc.include.time`
`24`	`24`	`libc.include.uchar`
`25`	`25`	`libc.include.wchar`
	`26`	`+ libc.include.wctype`
`26`	`27`	`)`
Original file line number	Diff line number	Diff line change
`@@ -99,6 +99,9 @@ set(TARGET_LIBC_ENTRYPOINTS`
`99`	`99`	`libc.src.stdlib.calloc`
`100`	`100`	`libc.src.stdlib.realloc`
`101`	`101`	`libc.src.stdlib.free`
	`102`	`+`
	`103`	`+ # wctype.h entrypoints`
	`104`	`+ libc.src.wctype.iswalpha`
`102`	`105`	`)`
`103`	`106`
`104`	`107`	`if(LLVM_LIBC_FULL_BUILD)`
Original file line number	Diff line number	Diff line change
`@@ -11,4 +11,5 @@ set(TARGET_PUBLIC_HEADERS`
`11`	`11`	`libc.include.stdlib`
`12`	`12`	`libc.include.string`
`13`	`13`	`libc.include.strings`
	`14`	`+ libc.include.wctype`
`14`	`15`	`)`
Original file line number	Diff line number	Diff line change
`@@ -57,4 +57,5 @@ set(TARGET_PUBLIC_HEADERS`
`57`	`57`	`libc.include.uchar`
`58`	`58`	`libc.include.unistd`
`59`	`59`	`libc.include.wchar`
	`60`	`+ libc.include.wctype`
`60`	`61`	`)`
Original file line number	Diff line number	Diff line change
`@@ -191,6 +191,9 @@ set(TARGET_LIBC_ENTRYPOINTS`
`191`	`191`	`# sys/time.h entrypoints`
`192`	`192`	`libc.src.sys.time.setitimer`
`193`	`193`	`libc.src.sys.time.getitimer`
	`194`	`+`
	`195`	`+ # wctype.h entrypoints`
	`196`	`+ libc.src.wctype.iswalpha`
`194`	`197`	`)`
`195`	`198`
`196`	`199`	`if(LLVM_LIBC_FULL_BUILD)`