[libcxx-commits] [libcxx] 7f9f82e - [libc++][format] P3142R0: Printing Blank Lines with `println` (#87277)
via libcxx-commits
libcxx-commits at lists.llvm.org
Sat Apr 6 11:52:55 PDT 2024
Author: Hristo Hristov
Date: 2024-04-06T21:52:52+03:00
New Revision: 7f9f82e3de94040ca6124a43f2d737201bd4a595
URL: https://github.com/llvm/llvm-project/commit/7f9f82e3de94040ca6124a43f2d737201bd4a595
DIFF: https://github.com/llvm/llvm-project/commit/7f9f82e3de94040ca6124a43f2d737201bd4a595.diff
LOG: [libc++][format] P3142R0: Printing Blank Lines with `println` (#87277)
Implements https://wg21.link/P3142R0
Applied retroactively as DR, same as stdlibc++ and MS STL:
https://github.com/orgs/microsoft/projects/1143?pane=issue&itemId=57457187
Added:
libcxx/test/std/input.output/iostream.format/print.fun/println.blank_line.sh.cpp
Modified:
libcxx/docs/ReleaseNotes/19.rst
libcxx/docs/Status/Cxx2cPapers.csv
libcxx/include/ostream
libcxx/include/print
libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.formatted.print/locale-specific_form.pass.cpp
libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.formatted.print/println.pass.cpp
libcxx/test/std/input.output/iostream.format/print.fun/no_file_description.pass.cpp
libcxx/test/std/input.output/iostream.format/print.fun/println.file.pass.cpp
Removed:
################################################################################
diff --git a/libcxx/docs/ReleaseNotes/19.rst b/libcxx/docs/ReleaseNotes/19.rst
index 633fba08eec220..eaba5c8d0456dc 100644
--- a/libcxx/docs/ReleaseNotes/19.rst
+++ b/libcxx/docs/ReleaseNotes/19.rst
@@ -44,6 +44,7 @@ Implemented Papers
- P2495R3 - Interfacing ``stringstream``\s with ``string_view``
- P2867R2 - Remove Deprecated ``strstream``\s From C++26
- P2872R3 - Remove ``wstring_convert`` From C++26
+- P3142R0 - Printing Blank Lines with ``println`` (as DR against C++23)
- P2302R4 - ``std::ranges::contains``
- P1659R3 - ``std::ranges::starts_with`` and ``std::ranges::ends_with``
diff --git a/libcxx/docs/Status/Cxx2cPapers.csv b/libcxx/docs/Status/Cxx2cPapers.csv
index af270150fda0c0..fa11da62bc080e 100644
--- a/libcxx/docs/Status/Cxx2cPapers.csv
+++ b/libcxx/docs/Status/Cxx2cPapers.csv
@@ -51,7 +51,7 @@
"`P2869R4 <https://wg21.link/P2869R4>`__","LWG","Remove Deprecated ``shared_ptr`` Atomic Access APIs from C++26","Tokyo March 2024","","",""
"`P2872R3 <https://wg21.link/P2872R3>`__","LWG","Remove ``wstring_convert`` >From C++26","Tokyo March 2024","|Complete|","19.0",""
"`P3107R5 <https://wg21.link/P3107R5>`__","LWG","Permit an efficient implementation of ``std::print``","Tokyo March 2024","","","|format| |DR|"
-"`P3142R0 <https://wg21.link/P3142R0>`__","LWG","Printing Blank Lines with ``println``","Tokyo March 2024","","","|format|"
+"`P3142R0 <https://wg21.link/P3142R0>`__","LWG","Printing Blank Lines with ``println``","Tokyo March 2024","|Complete|","19.0","|format|"
"`P2845R8 <https://wg21.link/P2845R8>`__","LWG","Formatting of ``std::filesystem::path``","Tokyo March 2024","","","|format|"
"`P0493R5 <https://wg21.link/P0493R5>`__","LWG","Atomic minimum/maximum","Tokyo March 2024","","",""
"`P2542R8 <https://wg21.link/P2542R8>`__","LWG","``views::concat``","Tokyo March 2024","","","|ranges|"
diff --git a/libcxx/include/ostream b/libcxx/include/ostream
index 42819ceb252c65..d4fc1c58b8a941 100644
--- a/libcxx/include/ostream
+++ b/libcxx/include/ostream
@@ -164,6 +164,7 @@ template<class... Args>
void print(ostream& os, format_string<Args...> fmt, Args&&... args);
template<class... Args> // since C++23
void println(ostream& os, format_string<Args...> fmt, Args&&... args);
+void println(ostream& os); // since C++26
void vprint_unicode(ostream& os, string_view fmt, format_args args); // since C++23
void vprint_nonunicode(ostream& os, string_view fmt, format_args args); // since C++23
@@ -1163,6 +1164,9 @@ _LIBCPP_HIDE_FROM_ABI void println(ostream& __os, format_string<_Args...> __fmt,
# endif // _LIBCPP_HAS_NO_UNICODE
}
+template <class = void> // TODO PRINT template or availability markup fires too eagerly (http://llvm.org/PR61563).
+_LIBCPP_HIDE_FROM_ABI inline void println(ostream& __os) { std::print(__os, "\n"); }
+
#endif // _LIBCPP_STD_VER >= 23
_LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/print b/libcxx/include/print
index a9f10433a7dc61..e0bcf214ea239b 100644
--- a/libcxx/include/print
+++ b/libcxx/include/print
@@ -15,8 +15,10 @@ namespace std {
// [print.fun], print functions
template<class... Args>
void print(format_string<Args...> fmt, Args&&... args);
+ void println(); // Since C++26
template<class... Args>
void print(FILE* stream, format_string<Args...> fmt, Args&&... args);
+ void println(FILE* stream); // Since C++26
template<class... Args>
void println(format_string<Args...> fmt, Args&&... args);
@@ -356,6 +358,12 @@ _LIBCPP_HIDE_FROM_ABI void println(FILE* __stream, format_string<_Args...> __fmt
# endif // _LIBCPP_HAS_NO_UNICODE
}
+template <class = void> // TODO PRINT template or availability markup fires too eagerly (http://llvm.org/PR61563).
+_LIBCPP_HIDE_FROM_ABI inline void println(FILE* __stream) { std::print(__stream, "\n"); }
+
+template <class = void> // TODO PRINT template or availability markup fires too eagerly (http://llvm.org/PR61563).
+_LIBCPP_HIDE_FROM_ABI inline void println() { println(stdout); }
+
template <class... _Args>
_LIBCPP_HIDE_FROM_ABI void println(format_string<_Args...> __fmt, _Args&&... __args) {
std::println(stdout, __fmt, std::forward<_Args>(__args)...);
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.formatted.print/locale-specific_form.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.formatted.print/locale-specific_form.pass.cpp
index 6b62e2f1754de5..2e19e38e2ed04f 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.formatted.print/locale-specific_form.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.formatted.print/locale-specific_form.pass.cpp
@@ -26,6 +26,7 @@
// void print(ostream& os, format_string<Args...> fmt, Args&&... args);
// template<class... Args>
// void println(ostream& os, format_string<Args...> fmt, Args&&... args);
+// void println(ostream& os); // since C++26
//
// void vprint_unicode(ostream& os, string_view fmt, format_args args);
// void vprint_nonunicode(ostream& os, string_view fmt, format_args args);
@@ -67,7 +68,7 @@ test(std::stringstream& stream, std::string expected, test_format_string<char, A
// *** vprint_unicode ***
{
stream.str("");
- ;
+
std::vprint_unicode(stream, fmt.get(), std::make_format_args(args...));
std::string out = stream.str();
TEST_REQUIRE(out == expected,
@@ -77,7 +78,7 @@ test(std::stringstream& stream, std::string expected, test_format_string<char, A
// *** vprint_nonunicode ***
{
stream.str("");
- ;
+
std::vprint_nonunicode(stream, fmt.get(), std::make_format_args(args...));
std::string out = stream.str();
TEST_REQUIRE(out == expected,
@@ -88,7 +89,7 @@ test(std::stringstream& stream, std::string expected, test_format_string<char, A
{
expected += '\n'; // Tested last since it changes the expected value.
stream.str("");
- ;
+
std::println(stream, fmt, std::forward<Args>(args)...);
std::string out = stream.str();
TEST_REQUIRE(out == expected,
@@ -111,6 +112,7 @@ static void test(std::string expected, std::locale loc, test_format_string<char,
}
#ifndef TEST_HAS_NO_UNICODE
+
struct numpunct_unicode : std::numpunct<char> {
string_type do_truename() const override { return "gültig"; }
string_type do_falsename() const override { return "ungültig"; }
@@ -2188,12 +2190,47 @@ static void test_floating_point() {
test_floating_point_default_precision<F>();
}
+static void test_println_blank_line(std::stringstream& stream) {
+ std::string expected{'\n'};
+ stream.str("");
+
+ std::println(stream);
+ std::string out = stream.str();
+ TEST_REQUIRE(out == expected,
+ TEST_WRITE_CONCATENATED("\nExpected output (blank line) ", expected, "\nActual output ", out, '\n'));
+}
+
+static void test_println_blank_line(std::locale loc) {
+ std::stringstream stream;
+ stream.imbue(loc);
+ test_println_blank_line(stream);
+}
+
+static void test_println_blank_line() {
+ std::locale::global(std::locale(LOCALE_en_US_UTF_8));
+ assert(std::locale().name() == LOCALE_en_US_UTF_8);
+ std::stringstream stream;
+ test_println_blank_line(stream);
+
+ std::locale loc = std::locale(std::locale(), new numpunct<char>());
+ std::locale::global(loc);
+ test_println_blank_line(std::locale(LOCALE_en_US_UTF_8));
+
+#ifndef TEST_HAS_NO_UNICODE
+
+ std::locale loc_unicode = std::locale(std::locale(), new numpunct_unicode());
+ test_println_blank_line(loc_unicode);
+
+#endif // TEST_HAS_NO_UNICODE
+}
+
int main(int, char**) {
test_bool();
test_integer();
test_floating_point<float>();
test_floating_point<double>();
test_floating_point<long double>();
+ test_println_blank_line();
return 0;
}
diff --git a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.formatted.print/println.pass.cpp b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.formatted.print/println.pass.cpp
index 479a3de0a93c8d..19a02638a9da18 100644
--- a/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.formatted.print/println.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/output.streams/ostream.formatted/ostream.formatted.print/println.pass.cpp
@@ -17,6 +17,7 @@
// template<class... Args>
// void println(ostream& os, format_string<Args...> fmt, Args&&... args);
+// void println(ostream& os); // since C++26
// [ostream.formatted.print]/3
// If the function is vprint_unicode and os is a stream that refers to
@@ -55,8 +56,20 @@ auto test_exception = []<class... Args>(std::string_view, std::string_view, Args
// The exceptions are tested by other functions that don't use the basic-format-string as fmt argument.
};
+void test_println_blank_line() {
+ std::string expected{'\n'};
+
+ std::stringstream sstr;
+ std::println(sstr);
+
+ std::string out = sstr.str();
+ TEST_REQUIRE(out == expected,
+ TEST_WRITE_CONCATENATED("\nExpected output (blank line) ", expected, "\nActual output ", out, '\n'));
+};
+
int main(int, char**) {
print_tests(test_file, test_exception);
+ test_println_blank_line();
return 0;
}
diff --git a/libcxx/test/std/input.output/iostream.format/print.fun/no_file_description.pass.cpp b/libcxx/test/std/input.output/iostream.format/print.fun/no_file_description.pass.cpp
index f502616b677b77..ffa48c5e745d65 100644
--- a/libcxx/test/std/input.output/iostream.format/print.fun/no_file_description.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/print.fun/no_file_description.pass.cpp
@@ -25,8 +25,10 @@
// template<class... Args>
// void print(FILE* stream, format_string<Args...> fmt, Args&&... args);
+// void println(); // Since C++26
// template<class... Args>
// void println(FILE* stream, format_string<Args...> fmt, Args&&... args);
+// void println(FILE* stream); // Since C++26
// void vprint_unicode(FILE* stream, string_view fmt, format_args args);
// void vprint_nonunicode(FILE* stream, string_view fmt, format_args args);
@@ -63,6 +65,20 @@ static void test_println() {
assert(std::string_view(buffer.data(), pos) == "hello world!\n");
}
+static void test_println_blank_line() {
+ std::array<char, 100> buffer{0};
+
+ FILE* file = fmemopen(buffer.data(), buffer.size(), "wb");
+ assert(file);
+
+ std::println(file);
+ long pos = std::ftell(file);
+ std::fclose(file);
+
+ assert(pos > 0);
+ assert(std::string_view(buffer.data(), pos) == "\n");
+}
+
static void test_vprint_unicode() {
std::array<char, 100> buffer{0};
@@ -96,6 +112,7 @@ static void test_vprint_nonunicode() {
int main(int, char**) {
test_print();
test_println();
+ test_println_blank_line();
test_vprint_unicode();
test_vprint_nonunicode();
diff --git a/libcxx/test/std/input.output/iostream.format/print.fun/println.blank_line.sh.cpp b/libcxx/test/std/input.output/iostream.format/print.fun/println.blank_line.sh.cpp
new file mode 100644
index 00000000000000..93c3563d501b20
--- /dev/null
+++ b/libcxx/test/std/input.output/iostream.format/print.fun/println.blank_line.sh.cpp
@@ -0,0 +1,48 @@
+//===----------------------------------------------------------------------===//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
+// UNSUPPORTED: no-filesystem
+// UNSUPPORTED: executor-has-no-bash
+// UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
+
+// FIXME PRINT How to test println on Windows?
+// XFAIL: msvc, target={{.+}}-windows-gnu
+
+// XFAIL: availability-fp_to_chars-missing
+
+// <print>
+
+// void println();
+
+// Testing this properly is quite hard; the function unconditionally
+// writes to stdout. When stdout is redirected to a file it is no longer
+// considered a terminal. The function is a small wrapper around
+//
+// template<class... Args>
+// void println(FILE* stream, format_string<Args...> fmt, Args&&... args);
+//
+// So do minimal tests for this function and rely on the FILE* overload
+// to do more testing.
+//
+// The testing is based on the testing for std::cout.
+
+// TODO PRINT Use lit builtin echo
+
+// FILE_DEPENDENCIES: echo.sh
+// RUN: %{build}
+// RUN: %{exec} bash echo.sh -ne "\n" > %t.expected
+// RUN: %{exec} "%t.exe" > %t.actual
+// RUN:
diff -u %t.actual %t.expected
+
+#include <print>
+
+int main(int, char**) {
+ std::println();
+
+ return 0;
+}
diff --git a/libcxx/test/std/input.output/iostream.format/print.fun/println.file.pass.cpp b/libcxx/test/std/input.output/iostream.format/print.fun/println.file.pass.cpp
index 07272ebb57e5fc..2f088e7a7db5f2 100644
--- a/libcxx/test/std/input.output/iostream.format/print.fun/println.file.pass.cpp
+++ b/libcxx/test/std/input.output/iostream.format/print.fun/println.file.pass.cpp
@@ -129,6 +129,29 @@ static void test_new_line() {
}
}
+static void test_println_blank_line() {
+ // Text does newline translation.
+ {
+ FILE* file = fopen(filename.c_str(), "w");
+ assert(file);
+
+ std::println(file);
+#ifndef _WIN32
+ assert(std::ftell(file) == 1);
+#else
+ assert(std::ftell(file) == 2);
+#endif
+ }
+ // Binary no newline translation.
+ {
+ FILE* file = fopen(filename.c_str(), "wb");
+ assert(file);
+
+ std::println(file);
+ assert(std::ftell(file) == 1);
+ }
+}
+
int main(int, char**) {
print_tests(test_file, test_exception);
@@ -137,6 +160,7 @@ int main(int, char**) {
#endif
test_read_only();
test_new_line();
+ test_println_blank_line();
return 0;
}
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