Make poll() the default (#2065)

* Make poll() the default

select() can still be enabled by defining CPPHTTPLIB_USE_SELECT.

* Run tests with select() and poll()

.github/workflows/test.yaml

@@ -43,14 +43,21 @@ jobs:
       (github.event_name == 'pull_request'  &&
        github.event.pull_request.head.repo.full_name != github.event.pull_request.base.repo.full_name) ||
       (github.event_name == 'workflow_dispatch' && github.event.inputs.test_linux == 'true')
+    strategy:
+      matrix:
+        select_impl: ['select', 'poll']
     steps:
       - name: checkout
         uses: actions/checkout@v4
       - name: install libraries
         run: sudo apt-get update && sudo apt-get install -y libbrotli-dev libcurl4-openssl-dev
       - name: build and run tests
+        env:
+          SELECT_IMPL: ${{ matrix.select_impl }}
         run: cd test && make
       - name: run fuzz test target
+        env:
+          SELECT_IMPL: ${{ matrix.select_impl }}
         run: cd test && make fuzz_test
 
   macos:
@@ -60,12 +67,19 @@ jobs:
       (github.event_name == 'pull_request'  &&
        github.event.pull_request.head.repo.full_name != github.event.pull_request.base.repo.full_name) ||
       (github.event_name == 'workflow_dispatch' && github.event.inputs.test_macos == 'true')
+    strategy:
+      matrix:
+        select_impl: ['select', 'poll']
     steps:
       - name: checkout
         uses: actions/checkout@v4
       - name: build and run tests
+        env:
+          SELECT_IMPL: ${{ matrix.select_impl }}
         run: cd test && make
       - name: run fuzz test target
+        env:
+          SELECT_IMPL: ${{ matrix.select_impl }}
         run: cd test && make fuzz_test
 
   windows:
@@ -75,6 +89,9 @@ jobs:
       (github.event_name == 'pull_request'  &&
        github.event.pull_request.head.repo.full_name != github.event.pull_request.base.repo.full_name) ||
       (github.event_name == 'workflow_dispatch' && github.event.inputs.test_windows == 'true')
+    strategy:
+      matrix:
+        select_impl: ['select', 'poll']
     steps:
     - name: Prepare Git for Checkout on Windows
       run: |
@@ -96,16 +113,33 @@ jobs:
         choco install openssl
 
     - name: Configure CMake with SSL
-      run: cmake -B build -S . -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=${{ env.VCPKG_ROOT }}/scripts/buildsystems/vcpkg.cmake -DHTTPLIB_TEST=ON -DHTTPLIB_REQUIRE_OPENSSL=ON -DHTTPLIB_REQUIRE_ZLIB=ON -DHTTPLIB_REQUIRE_BROTLI=ON
+      run: >
+        cmake -B build -S .
+        -DCMAKE_BUILD_TYPE=Release
+        -DCMAKE_TOOLCHAIN_FILE=${{ env.VCPKG_ROOT }}/scripts/buildsystems/vcpkg.cmake
+        -DHTTPLIB_TEST=ON
+        -DHTTPLIB_REQUIRE_OPENSSL=ON
+        -DHTTPLIB_REQUIRE_ZLIB=ON
+        -DHTTPLIB_REQUIRE_BROTLI=ON
+        -DHTTPLIB_USE_SELECT=${{ matrix.select_impl == 'select' && 'ON' || 'OFF' }}
     - name: Build with with SSL
-      run: cmake --build build --config Release
+      run: cmake --build build --config Release -- /v:m /clp:ShowCommandLine /nologo
     - name: Run tests with SSL
       run: ctest --output-on-failure --test-dir build -C Release
 
     - name: Configure CMake without SSL
-      run: cmake -B build-no-ssl -S . -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=${{ env.VCPKG_ROOT }}/scripts/buildsystems/vcpkg.cmake -DHTTPLIB_TEST=ON -DHTTPLIB_REQUIRE_OPENSSL=OFF -DHTTPLIB_REQUIRE_ZLIB=ON -DHTTPLIB_REQUIRE_BROTLI=ON
+      run: >
+        cmake -B build-no-ssl -S .
+        -DCMAKE_BUILD_TYPE=Release
+        -DCMAKE_TOOLCHAIN_FILE=${{ env.VCPKG_ROOT }}/scripts/buildsystems/vcpkg.cmake
+        -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
+        -DHTTPLIB_TEST=ON
+        -DHTTPLIB_REQUIRE_OPENSSL=OFF
+        -DHTTPLIB_REQUIRE_ZLIB=ON
+        -DHTTPLIB_REQUIRE_BROTLI=ON
+        -DHTTPLIB_USE_SELECT=${{ matrix.select_impl == 'select' && 'ON' || 'OFF' }}
     - name: Build without SSL
-      run: cmake --build build-no-ssl --config Release
+      run: cmake --build build-no-ssl --config Release -- /v:m /clp:ShowCommandLine /nologo
     - name: Run tests without SSL
       run: ctest --output-on-failure --test-dir build-no-ssl -C Release
     env:

CMakeLists.txt

@@ -8,6 +8,7 @@
 	* HTTPLIB_REQUIRE_ZLIB (default off)
 	* HTTPLIB_REQUIRE_BROTLI (default off)
 	* HTTPLIB_USE_CERTS_FROM_MACOSX_KEYCHAIN (default on)
+	* HTTPLIB_USE_SELECT (default off) choose between select() and poll()
 	* HTTPLIB_COMPILE (default off)
 	* HTTPLIB_INSTALL (default on)
 	* HTTPLIB_TEST (default off)
@@ -46,6 +47,7 @@
 	* HTTPLIB_IS_USING_ZLIB - a bool for if ZLIB support is enabled.
 	* HTTPLIB_IS_USING_BROTLI - a bool for if Brotli support is enabled.
 	* HTTPLIB_IS_USING_CERTS_FROM_MACOSX_KEYCHAIN - a bool for if support of loading system certs from the Apple Keychain is enabled.
+	* HTTPLIB_IS_USING_SELECT - a bool for if select() is used instead of poll().
 	* HTTPLIB_IS_COMPILED - a bool for if the library is compiled, or otherwise header-only.
 	* HTTPLIB_INCLUDE_DIR - the root path to httplib's header (e.g. /usr/include).
 	* HTTPLIB_LIBRARY - the full path to the library if compiled (e.g. /usr/lib/libhttplib.so).
@@ -101,6 +103,7 @@ option(HTTPLIB_TEST "Enables testing and builds tests" OFF)
 option(HTTPLIB_REQUIRE_BROTLI "Requires Brotli to be found & linked, or fails build." OFF)
 option(HTTPLIB_USE_BROTLI_IF_AVAILABLE "Uses Brotli (if available) to enable Brotli decompression support." ON)
 option(HTTPLIB_USE_CERTS_FROM_MACOSX_KEYCHAIN "Enable feature to load system certs from the Apple Keychain." ON)
+option(HTTPLIB_USE_SELECT "Uses select() instead of poll()." OFF)
 # Defaults to static library
 option(BUILD_SHARED_LIBS "Build the library as a shared library instead of static. Has no effect if using header-only." OFF)
 if (BUILD_SHARED_LIBS AND WIN32 AND HTTPLIB_COMPILE)
@@ -112,6 +115,7 @@ endif()
 # Set some variables that are used in-tree and while building based on our options
 set(HTTPLIB_IS_COMPILED ${HTTPLIB_COMPILE})
 set(HTTPLIB_IS_USING_CERTS_FROM_MACOSX_KEYCHAIN ${HTTPLIB_USE_CERTS_FROM_MACOSX_KEYCHAIN})
+set(HTTPLIB_IS_USING_SELECT ${HTTPLIB_USE_SELECT})
 
 # Threads needed for <thread> on some systems, and for <pthread.h> on Linux
 set(THREADS_PREFER_PTHREAD_FLAG TRUE)
@@ -238,6 +242,7 @@ target_compile_definitions(${PROJECT_NAME} ${_INTERFACE_OR_PUBLIC}
 	$<$<BOOL:${HTTPLIB_IS_USING_ZLIB}>:CPPHTTPLIB_ZLIB_SUPPORT>
 	$<$<BOOL:${HTTPLIB_IS_USING_OPENSSL}>:CPPHTTPLIB_OPENSSL_SUPPORT>
 	$<$<AND:$<PLATFORM_ID:Darwin>,$<BOOL:${HTTPLIB_IS_USING_OPENSSL}>,$<BOOL:${HTTPLIB_IS_USING_CERTS_FROM_MACOSX_KEYCHAIN}>>:CPPHTTPLIB_USE_CERTS_FROM_MACOSX_KEYCHAIN>
+	$<$<BOOL:${HTTPLIB_IS_USING_SELECT}>:CPPHTTPLIB_USE_SELECT>
 )
 
 # CMake configuration files installation directory

Dockerfile

@@ -2,7 +2,7 @@ FROM yhirose4dockerhub/ubuntu-builder AS builder
 WORKDIR /build
 COPY httplib.h .
 COPY docker/main.cc .
-RUN g++ -std=c++23 -static -o server -O2 -I. -DCPPHTTPLIB_USE_POLL main.cc && strip server
+RUN g++ -std=c++23 -static -o server -O2 -I. main.cc && strip server
 
 FROM scratch
 COPY --from=builder /build/server /server

README.md

@@ -872,10 +872,10 @@ res->body; // Compressed data
 
 ```
 
-Use `poll` instead of `select`
+Use `select()` instead of `poll()`
-------------------------------
+----------------------------------
 
-`select` system call is used as default since it's more widely supported. If you want to let cpp-httplib use `poll` instead, you can do so with `CPPHTTPLIB_USE_POLL`.
+cpp-httplib defaults to the widely supported `poll()` system call. If your OS lacks support for `poll()`, define `CPPHTTPLIB_USE_SELECT` to use `select()` instead.
 
 Unix Domain Socket Support
 --------------------------

httplib.h

@@ -145,6 +145,12 @@
 #define CPPHTTPLIB_LISTEN_BACKLOG 5
 #endif
 
+#if !defined(CPPHTTPLIB_USE_POLL) && !defined(CPPHTTPLIB_USE_SELECT)
+#define CPPHTTPLIB_USE_POLL
+#elif defined(CPPHTTPLIB_USE_POLL) && defined(CPPHTTPLIB_USE_SELECT)
+#error "CPPHTTPLIB_USE_POLL and CPPHTTPLIB_USE_SELECT are mutually exclusive"
+#endif
+
 /*
  * Headers
  */

test/Makefile

@@ -1,6 +1,10 @@
 CXX = clang++
 CXXFLAGS = -g -std=c++11 -I. -Wall -Wextra -Wtype-limits -Wconversion -Wshadow # -fno-exceptions -DCPPHTTPLIB_NO_EXCEPTIONS -fsanitize=address
 
+ifeq ($(SELECT_IMPL),select)
+    CXXFLAGS += -DCPPHTTPLIB_USE_SELECT
+endif
+
 PREFIX ?= $(shell brew --prefix)
 
 OPENSSL_DIR = $(PREFIX)/opt/openssl@3