Add BUILD_SHARED_LIBS support (fix dacap#23)

Author: dacap

.github/workflows/build.yml

@@ -7,7 +7,9 @@ jobs:
       fail-fast: false
       matrix:
         os: [windows-latest, macos-latest, ubuntu-latest]
-        enable_image: [on, off]
+        sanitize: [address, none]
+        shared: [shared, static]
+        enable_image: [with_image, text_only]
     steps:
     - uses: actions/checkout@v4
     - uses: ilammy/msvc-dev-cmd@v1
@@ -21,14 +23,39 @@ jobs:
     - name: Generating Makefiles
       shell: bash
       run: |
+        if [[ "${{ matrix.shared }}" == "shared" ]] ; then
+          shared=on
+        else
+          shared=off
+        fi
+        if [[ "${{ matrix.enable_image }}" == "with_image" ]] ; then
+          with_image=on
+        else
+          with_image=off
+        fi
         if [[ "${{ runner.os }}" == "Windows" ]] ; then
-          cmake . -G "NMake Makefiles" \
-                  -DCLIP_ENABLE_IMAGE=${{ matrix.enable_image }} \
-                  "-DCMAKE_CXX_FLAGS:STRING=-DWIN32 -D_WINDOWS -GR -EHsc -fsanitize=address" \
-                  "-DCMAKE_EXE_LINKER_FLAGS:STRING=-machine:x64 -fsanitize=address"
+          if [[ "${{ runner.sanitize }}" == "address" ]] ; then
+            cmake . -G "NMake Makefiles" \
+              -DCLIP_ENABLE_IMAGE=${{ matrix.enable_image }} \
+              "-DCMAKE_CXX_FLAGS:STRING=-DWIN32 -D_WINDOWS -GR -EHsc -fsanitize=address" \
+              "-DCMAKE_EXE_LINKER_FLAGS:STRING=-machine:x64 -fsanitize=address"
+          else
+            cmake . -G "NMake Makefiles" \
+              -DCLIP_ENABLE_IMAGE=${{ matrix.enable_image }} \
+              -DBUILD_SHARED_LIBS=$shared
+          fi
         else
-          cmake . -G "Unix Makefiles" \
-                  -DCLIP_ENABLE_IMAGE=${{ matrix.enable_image }}
+          if [[ "${{ runner.sanitize }}" == "address" ]] ; then
+            cmake . -G "Unix Makefiles" \
+              -DCLIP_ENABLE_IMAGE=${{ matrix.enable_image }} \
+              "-DCMAKE_CXX_FLAGS:STRING=-fsanitize=address" \
+              "-DCMAKE_EXE_LINKER_FLAGS:STRING=-fsanitize=address" \
+              -DBUILD_SHARED_LIBS=$shared
+            else
+              cmake . -G "Unix Makefiles" \
+                "-DCLIP_ENABLE_IMAGE=$with_image" \
+                -DBUILD_SHARED_LIBS=$shared
+            fi
         fi
     - name: Compiling
       shell: bash

CMakeLists.txt

@@ -1,20 +1,20 @@
 # Clip Library
-# Copyright (c) 2015-2025 David Capello
+# Copyright (c) 2015-2026 David Capello
 
 cmake_minimum_required(VERSION 3.15)
 
 project(clip LANGUAGES CXX)
 
 set(CMAKE_CXX_STANDARD 11)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
-set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS ON)
 
 if(CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")
   # Use libc++ explicitly so we can compile for
   # CMAKE_OSX_DEPLOYMENT_TARGET=10.7 or 10.8
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libc++")
 endif()
 
+option(BUILD_SHARED_LIBS "Build clip as a shared library" off)
 option(CLIP_ENABLE_IMAGE "Compile with support to copy/paste images" on)
 if(WIN32)
   option(CLIP_ENABLE_LIST_FORMATS "Compile with support to list clipboard formats" off)
@@ -29,6 +29,10 @@ endif()
 add_library(clip clip.cpp)
 
 target_include_directories(clip INTERFACE $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
+target_compile_definitions(clip PRIVATE -DCLIP_BUILDING_LIB=1)
+if(BUILD_SHARED_LIBS)
+  target_compile_definitions(clip PUBLIC -DCLIP_SHARED=1)
+endif()
 
 if(CLIP_ENABLE_IMAGE)
   target_sources(clip PRIVATE image.cpp)
@@ -102,11 +106,27 @@ endif()
 
 if(CLIP_EXAMPLES)
   add_subdirectory(examples)
+  if(WIN32 AND BUILD_SHARED_LIBS)
+    add_custom_command(
+      TARGET clip
+      BYPRODUCTS ${CMAKE_CURRENT_BINARY_DIR}/examples/clip.dll
+      POST_BUILD
+      COMMAND ${CMAKE_COMMAND} -E copy $<TARGET_FILE:clip> ${CMAKE_CURRENT_BINARY_DIR}/examples
+      COMMENT "Copy DLL to examples directory")
+  endif()
 endif()
 
 if(CLIP_TESTS)
   enable_testing()
   add_subdirectory(tests)
+  if(WIN32 AND BUILD_SHARED_LIBS)
+    add_custom_command(
+      TARGET clip
+      BYPRODUCTS ${CMAKE_CURRENT_BINARY_DIR}/tests/clip.dll
+      POST_BUILD
+      COMMAND ${CMAKE_COMMAND} -E copy $<TARGET_FILE:clip> ${CMAKE_CURRENT_BINARY_DIR}/tests
+      COMMENT "Copy DLL to tests directory")
+  endif()
 endif()
 
 if(CLIP_INSTALL)

LICENSE.txt

@@ -1,4 +1,4 @@
-Copyright (c) 2015-2025 David Capello
+Copyright (c) 2015-2026 David Capello
 
 Permission is hereby granted, free of charge, to any person obtaining
 a copy of this software and associated documentation files (the

README.md

@@ -1,5 +1,5 @@
 # Clip Library
-*Copyright (c) 2015-2025 David Capello*
+*Copyright (c) 2015-2026 David Capello*
 
 [![build](https://github.com/dacap/clip/workflows/build/badge.svg)](https://github.com/dacap/clip/actions?query=workflow%3Abuild)
 [![MIT Licensed](https://img.shields.io/badge/license-MIT-blue.svg)](LICENSE.txt)

clip.h

@@ -1,5 +1,5 @@
 // Clip Library
-// Copyright (c) 2015-2024 David Capello
+// Copyright (c) 2015-2026 David Capello
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -13,6 +13,8 @@
 #include <string>
 #include <vector>
 
+#include "clip_base.h"
+
 namespace clip {
 
   // ======================================================================
@@ -28,7 +30,7 @@ namespace clip {
 #endif // CLIP_ENABLE_IMAGE
 
 #if CLIP_ENABLE_LIST_FORMATS
-  struct format_info {
+  struct CLIP_EXTERN format_info {
     format id = 0;
     std::string name;
     format_info(const format id,
@@ -39,7 +41,7 @@ namespace clip {
   };
 #endif // CLIP_ENABLE_LIST_FORMATS
 
-  class lock {
+  class CLIP_EXTERN lock {
   public:
     // You can give your current HWND as the "native_window_handle."
     // Windows clipboard functions use this handle to open/close
@@ -84,24 +86,24 @@ namespace clip {
     std::unique_ptr<impl> p;
   };
 
-  format register_format(const std::string& name);
+  CLIP_EXTERN format register_format(const std::string& name);
 
   // This format is when the clipboard has no content.
-  format empty_format();
+  CLIP_EXTERN format empty_format();
 
   // When the clipboard has UTF8 text.
-  format text_format();
+  CLIP_EXTERN format text_format();
 
 #if CLIP_ENABLE_IMAGE
   // When the clipboard has an image.
-  format image_format();
+  CLIP_EXTERN format image_format();
 #endif
 
   // Returns true if the clipboard has content of the given type.
-  bool has(format f);
+  CLIP_EXTERN bool has(format f);
 
   // Clears the clipboard content.
-  bool clear();
+  CLIP_EXTERN bool clear();
 
   // ======================================================================
   // Error handling
@@ -116,25 +118,25 @@ namespace clip {
 
   typedef void (*error_handler)(ErrorCode code);
 
-  void set_error_handler(error_handler f);
-  error_handler get_error_handler();
+  CLIP_EXTERN void set_error_handler(error_handler f);
+  CLIP_EXTERN error_handler get_error_handler();
 
   // ======================================================================
   // Text
   // ======================================================================
 
   // High-level API to put/get UTF8 text in/from the clipboard. These
   // functions returns false in case of error.
-  bool set_text(const std::string& value);
-  bool get_text(std::string& value);
+  CLIP_EXTERN bool set_text(const std::string& value);
+  CLIP_EXTERN bool get_text(std::string& value);
 
   // ======================================================================
   // Image
   // ======================================================================
 
 #if CLIP_ENABLE_IMAGE
 
-  struct image_spec {
+  struct CLIP_EXTERN image_spec {
     unsigned long width = 0;
     unsigned long height = 0;
     unsigned long bits_per_pixel = 0;
@@ -161,7 +163,7 @@ namespace clip {
   // automatically. macOS handles straight alpha directly, so there is
   // no conversion at all. Linux/X11 images are transferred in
   // image/png format which are specified in straight alpha.
-  class image {
+  class CLIP_EXTERN image {
   public:
     image();
     image(const image_spec& spec);
@@ -190,9 +192,9 @@ namespace clip {
 
   // High-level API to set/get an image in/from the clipboard. These
   // functions returns false in case of error.
-  bool set_image(const image& img);
-  bool get_image(image& img);
-  bool get_image_spec(image_spec& spec);
+  CLIP_EXTERN bool set_image(const image& img);
+  CLIP_EXTERN bool get_image(image& img);
+  CLIP_EXTERN bool get_image_spec(image_spec& spec);
 
 #endif // CLIP_ENABLE_IMAGE
 
@@ -203,8 +205,8 @@ namespace clip {
   // Only for X11: Sets the time (in milliseconds) that we must wait
   // for the selection/clipboard owner to receive the content. This
   // value is 1000 (one second) by default.
-  void set_x11_wait_timeout(int msecs);
-  int get_x11_wait_timeout();
+  CLIP_EXTERN void set_x11_wait_timeout(int msecs);
+  CLIP_EXTERN int get_x11_wait_timeout();
 
 } // namespace clip
 

clip_base.h

@@ -0,0 +1,21 @@
+// Clip Library
+// Copyright (C) 2026 David Capello
+//
+// This file is released under the terms of the MIT license.
+// Read LICENSE.txt for more information.
+
+#ifndef CLIP_BASE_H_INCLUDED
+#define CLIP_BASE_H_INCLUDED
+#pragma once
+
+#if defined(_WIN32) && defined(CLIP_SHARED)
+  #ifdef CLIP_BUILDING_LIB
+    #define CLIP_EXTERN __declspec(dllexport)
+  #else
+    #define CLIP_EXTERN __declspec(dllimport)
+  #endif
+#else
+  #define CLIP_EXTERN
+#endif
+
+#endif // CLIP_H_INCLUDED

clip_osx.h

@@ -1,5 +1,5 @@
 // Clip Library
-// Copyright (c) 2024 David Capello
+// Copyright (c) 2024-2026 David Capello
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -12,6 +12,8 @@
 
 #include <Cocoa/Cocoa.h>
 
+#include "clip_base.h"
+
 namespace clip {
 
 class image;
@@ -21,9 +23,9 @@ namespace osx {
 
 #if CLIP_ENABLE_IMAGE
 
-bool get_image_from_clipboard(NSPasteboard* pasteboard,
-                              image* output_img,
-                              image_spec* output_spec);
+CLIP_EXTERN bool get_image_from_clipboard(NSPasteboard* pasteboard,
+                                          image* output_img,
+                                          image_spec* output_spec);
 
 #endif // CLIP_ENABLE_IMAGE
 

clip_win_bmp.h

@@ -1,5 +1,5 @@
 // Clip Library
-// Copyright (c) 2015-2025  David Capello
+// Copyright (c) 2015-2026  David Capello
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -16,14 +16,16 @@
 
 #include <windows.h>
 
+#include "clip_base.h"
+
 namespace clip {
 
 class image;
 struct image_spec;
 
 namespace win {
 
-struct BitmapInfo {
+struct CLIP_EXTERN BitmapInfo {
   BITMAPV5HEADER* b5 = nullptr;
   BITMAPINFO* bi = nullptr;
   int width = 0;
@@ -60,7 +62,7 @@ struct BitmapInfo {
 // Returns a handle to the HGLOBAL memory reserved to create a DIBV5
 // based on the image passed by parameter. Returns null if it cannot
 // create the handle.
-HGLOBAL create_dibv5(const image& image);
+CLIP_EXTERN HGLOBAL create_dibv5(const image& image);
 
 } // namespace win
 } // namespace clip

clip_win_hglobal.h

@@ -1,5 +1,5 @@
 // Clip Library
-// Copyright (c) 2025 David Capello
+// Copyright (c) 2025-2026 David Capello
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -12,11 +12,13 @@
 
 #include <algorithm>
 
+#include "clip_base.h"
+
 namespace clip {
 namespace win {
 
 // Scoped GlobalLock / GlobalUnlock wrapper
-class HglobalLock {
+class CLIP_EXTERN HglobalLock {
 public:
   HglobalLock() = delete;
   HglobalLock(const HglobalLock& other) = delete;
@@ -53,7 +55,7 @@ class HglobalLock {
 };
 
 // Scoped GlobalAlloc / GlobalFree wrapper
-class Hglobal {
+class CLIP_EXTERN Hglobal {
 public:
   Hglobal() : m_handle(nullptr) {
   }