【问题标题】：SDL2 library not found with Make but with CMake使用 Make 但使用 CMake 找不到 SDL2 库
【发布时间】：2016-06-14 16:40:54
【问题描述】：

我正在尝试在使用 Makefile 构建的项目中使用 SDL2、SDL2_ttf 和 SDL2_image。我尝试了许多不同的方法，但到目前为止，无论我尝试过什么，SDL2_ttf 和 SDL2_image 都会抛出类似于以下内容的错误。

/Library/Frameworks/SDL2_ttf.framework/Headers/SDL_ttf.h:34:10: fatal error: 
      'SDL2/SDL.h' file not found

我可以使用以下 CMakeLists 和值成功使用 CMake 构建项目。

cmake_minimum_required(VERSION 3.0)
project(kiss_sdl)


set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${kiss_sdl_SOURCE_DIR}/cmake")
set(BIN_DIR ${kiss_sdl_SOURCE_DIR}/bin)
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)

add_definitions(-DRESDIR=\"../../\")

find_package(SDL2 REQUIRED)
include_directories(${SDL2_INCLUDE_DIR})

find_package(SDL2_ttf REQUIRED)
include_directories(${SDL2_TTF_INCLUDE_DIR})

find_package(SDL2_image REQUIRED)
include_directories(${SDL2_IMAGE_INCLUDE_DIR})


add_executable(kiss_sdl kiss_example1.c kiss_draw.c kiss_general.c kiss_posix.c kiss_widgets.c kiss_sdl.h)


target_link_libraries(kiss_sdl ${SDL2_LIBRARY} ${SDL2_TTF_LIBRARY} ${SDL2_IMAGE_LIBRARY})
install(TARGETS kiss_sdl RUNTIME DESTINATION ${BIN_DIR})

我用来在 CMake 中查找 SDL 的 CMake 模块如下所示。

查找SDL2.cmake

# Locate SDL2 library
# This module defines
# SDL2_LIBRARY, the name of the library to link against
# SDL2_FOUND, if false, do not try to link to SDL2
# SDL2_INCLUDE_DIR, where to find SDL.h
#
# This module responds to the the flag:
# SDL2_BUILDING_LIBRARY
# If this is defined, then no SDL2_main will be linked in because
# only applications need main().
# Otherwise, it is assumed you are building an application and this
# module will attempt to locate and set the the proper link flags
# as part of the returned SDL2_LIBRARY variable.
#
# Don't forget to include SDL2main.h and SDL2main.m your project for the
# OS X framework based version. (Other versions link to -lSDL2main which
# this module will try to find on your behalf.) Also for OS X, this
# module will automatically add the -framework Cocoa on your behalf.
#
#
# Additional Note: If you see an empty SDL2_LIBRARY_TEMP in your configuration
# and no SDL2_LIBRARY, it means CMake did not find your SDL2 library
# (SDL2.dll, libsdl2.so, SDL2.framework, etc).
# Set SDL2_LIBRARY_TEMP to point to your SDL2 library, and configure again.
# Similarly, if you see an empty SDL2MAIN_LIBRARY, you should set this value
# as appropriate. These values are used to generate the final SDL2_LIBRARY
# variable, but when these values are unset, SDL2_LIBRARY does not get created.
#
#
# $SDL2 is an environment variable that would
# correspond to the ./configure --prefix=$SDL2
# used in building SDL2.
# l.e.galup 9-20-02
#
# Modified by Eric Wing.
# Added code to assist with automated building by using environmental variables
# and providing a more controlled/consistent search behavior.
# Added new modifications to recognize OS X frameworks and
# additional Unix paths (FreeBSD, etc).
# Also corrected the header search path to follow "proper" SDL2 guidelines.
# Added a search for SDL2main which is needed by some platforms.
# Added a search for threads which is needed by some platforms.
# Added needed compile switches for MinGW.
#
# On OSX, this will prefer the Framework version (if found) over others.
# People will have to manually change the cache values of
# SDL2_LIBRARY to override this selection or set the CMake environment
# CMAKE_INCLUDE_PATH to modify the search paths.
#
# Note that the header path has changed from SDL2/SDL.h to just SDL.h
# This needed to change because "proper" SDL2 convention
# is #include "SDL.h", not <SDL2/SDL.h>. This is done for portability
# reasons because not all systems place things in SDL2/ (see FreeBSD).
#
# Ported by Johnny Patterson. This is a literal port for SDL2 of the FindSDL.cmake
# module with the minor edit of changing "SDL" to "SDL2" where necessary. This
# was not created for redistribution, and exists temporarily pending official
# SDL2 CMake modules.
#
# Note that on windows this will only search for the 32bit libraries, to search
# for 64bit change x86/i686-w64 to x64/x86_64-w64

#=============================================================================
# Copyright 2003-2009 Kitware, Inc.
#
# CMake - Cross Platform Makefile Generator
# Copyright 2000-2014 Kitware, Inc.
# Copyright 2000-2011 Insight Software Consortium
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
#
# * Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# * Neither the names of Kitware, Inc., the Insight Software Consortium,
# nor the names of their contributors may be used to endorse or promote
# products derived from this software without specific prior written
# permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# This software is distributed WITHOUT ANY WARRANTY; without even the
# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# See the License for more information.
#=============================================================================
# (To distribute this file outside of CMake, substitute the full
# License text for the above reference.)

FIND_PATH(SDL2_INCLUDE_DIR SDL.h
    HINTS
    ${SDL2}
    $ENV{SDL2}
    PATH_SUFFIXES include/SDL2 include SDL2
    i686-w64-mingw32/include/SDL2
    x86_64-w64-mingw32/include/SDL2
    PATHS
    ~/Library/Frameworks
    /Library/Frameworks
    /usr/local/include/SDL2
    /usr/include/SDL2
    /sw # Fink
    /opt/local # DarwinPorts
    /opt/csw # Blastwave
    /opt
)

# Lookup the 64 bit libs on x64
IF(CMAKE_SIZEOF_VOID_P EQUAL 8)
    FIND_LIBRARY(SDL2_LIBRARY_TEMP SDL2
        HINTS
        ${SDL2}
        $ENV{SDL2}
        PATH_SUFFIXES lib64 lib
        lib/x64
        x86_64-w64-mingw32/lib
        PATHS
        /sw
        /opt/local
        /opt/csw
        /opt
    )
# On 32bit build find the 32bit libs
ELSE(CMAKE_SIZEOF_VOID_P EQUAL 8)
    FIND_LIBRARY(SDL2_LIBRARY_TEMP SDL2
        HINTS
        ${SDL2}
        $ENV{SDL2}
        PATH_SUFFIXES lib
        lib/x86
        i686-w64-mingw32/lib
        PATHS
        /sw
        /opt/local
        /opt/csw
        /opt
    )
ENDIF(CMAKE_SIZEOF_VOID_P EQUAL 8)

IF(NOT SDL2_BUILDING_LIBRARY)
    IF(NOT ${SDL2_INCLUDE_DIR} MATCHES ".framework")
        # Non-OS X framework versions expect you to also dynamically link to
        # SDL2main. This is mainly for Windows and OS X. Other (Unix) platforms
        # seem to provide SDL2main for compatibility even though they don't
        # necessarily need it.
        # Lookup the 64 bit libs on x64
        IF(CMAKE_SIZEOF_VOID_P EQUAL 8)
            FIND_LIBRARY(SDL2MAIN_LIBRARY
                NAMES SDL2main
                HINTS
                ${SDL2}
                $ENV{SDL2}
                PATH_SUFFIXES lib64 lib
                lib/x64
                x86_64-w64-mingw32/lib
                PATHS
                /sw
                /opt/local
                /opt/csw
                /opt
                )
            # On 32bit build find the 32bit libs
        ELSE(CMAKE_SIZEOF_VOID_P EQUAL 8)
            FIND_LIBRARY(SDL2MAIN_LIBRARY
                NAMES SDL2main
                HINTS
                ${SDL2}
                $ENV{SDL2}
                PATH_SUFFIXES lib
                lib/x86
                i686-w64-mingw32/lib
                PATHS
                /sw
                /opt/local
                /opt/csw
                /opt
                )
        ENDIF(CMAKE_SIZEOF_VOID_P EQUAL 8)
    ENDIF(NOT ${SDL2_INCLUDE_DIR} MATCHES ".framework")
ENDIF(NOT SDL2_BUILDING_LIBRARY)

# SDL2 may require threads on your system.
# The Apple build may not need an explicit flag because one of the
# frameworks may already provide it.
# But for non-OSX systems, I will use the CMake Threads package.
IF(NOT APPLE)
    FIND_PACKAGE(Threads)
ENDIF(NOT APPLE)

# MinGW needs an additional library, mwindows
# It's total link flags should look like -lmingw32 -lSDL2main -lSDL2 -lmwindows
# (Actually on second look, I think it only needs one of the m* libraries.)
IF(MINGW)
    SET(MINGW32_LIBRARY mingw32 CACHE STRING "mwindows for MinGW")
ENDIF(MINGW)

SET(SDL2_FOUND "NO")
    IF(SDL2_LIBRARY_TEMP)
        # For SDL2main
        IF(NOT SDL2_BUILDING_LIBRARY)
            IF(SDL2MAIN_LIBRARY)
                SET(SDL2_LIBRARY_TEMP ${SDL2MAIN_LIBRARY} ${SDL2_LIBRARY_TEMP})
            ENDIF(SDL2MAIN_LIBRARY)
        ENDIF(NOT SDL2_BUILDING_LIBRARY)

        # For OS X, SDL2 uses Cocoa as a backend so it must link to Cocoa.
        # CMake doesn't display the -framework Cocoa string in the UI even
        # though it actually is there if I modify a pre-used variable.
        # I think it has something to do with the CACHE STRING.
        # So I use a temporary variable until the end so I can set the
        # "real" variable in one-shot.
        IF(APPLE)
            SET(SDL2_LIBRARY_TEMP ${SDL2_LIBRARY_TEMP} "-framework Cocoa")
        ENDIF(APPLE)

        # For threads, as mentioned Apple doesn't need this.
        # In fact, there seems to be a problem if I used the Threads package
        # and try using this line, so I'm just skipping it entirely for OS X.
        IF(NOT APPLE)
            SET(SDL2_LIBRARY_TEMP ${SDL2_LIBRARY_TEMP} ${CMAKE_THREAD_LIBS_INIT})
        ENDIF(NOT APPLE)

        # For MinGW library
        IF(MINGW)
            SET(SDL2_LIBRARY_TEMP ${MINGW32_LIBRARY} ${SDL2_LIBRARY_TEMP})
        ENDIF(MINGW)

        # Set the final string here so the GUI reflects the final state.
        SET(SDL2_LIBRARY ${SDL2_LIBRARY_TEMP} CACHE STRING "Where the SDL2 Library can be found")
        # Set the temp variable to INTERNAL so it is not seen in the CMake GUI
        SET(SDL2_LIBRARY_TEMP "${SDL2_LIBRARY_TEMP}" CACHE INTERNAL "")

        SET(SDL2_FOUND "YES")
ENDIF(SDL2_LIBRARY_TEMP)

INCLUDE(FindPackageHandleStandardArgs)

FIND_PACKAGE_HANDLE_STANDARD_ARGS(SDL2 REQUIRED_VARS SDL2_LIBRARY SDL2_INCLUDE_DIR)

查找SDL2_ttf.cmake

# Locate SDL2_ttf library
# This module defines
# SDL2_TTF_LIBRARY, the name of the library to link against
# SDL2_TTF_FOUND, if false, do not try to link to SDL2_ttf
# SDL2_TTF_INCLUDE_DIR, where to find SDL_image.h
#
# Additional Note: If you see an empty SDL2_TTF_LIBRARY_TEMP in your configuration
# and no SDL2_TTF_LIBRARY, it means CMake did not find your SDL2_Image library
# (SDL2_ttf.dll, libsdl2_image.so, SDL2_ttf.framework, etc).
# Set SDL2_TTF_LIBRARY_TEMP to point to your SDL2 library, and configure again.
# Similarly, if you see an empty SDL2MAIN_LIBRARY, you should set this value
# as appropriate. These values are used to generate the final SDL2_TTF_LIBRARY
# variable, but when these values are unset, SDL2_TTF_LIBRARY does not get created.
#
# $SDL2 is an environment variable that would
# correspond to the ./configure --prefix=$SDL2
# used in building SDL2.
# l.e.galup 9-20-02
#
# Modified by Eric Wing.
# Added code to assist with automated building by using environmental variables
# and providing a more controlled/consistent search behavior.
# Added new modifications to recognize OS X frameworks and
# additional Unix paths (FreeBSD, etc).
# Also corrected the header search path to follow "proper" SDL2 guidelines.
# Added a search for SDL2main which is needed by some platforms.
# Added a search for threads which is needed by some platforms.
# Added needed compile switches for MinGW.
#
# On OSX, this will prefer the Framework version (if found) over others.
# People will have to manually change the cache values of
# SDL2_TTF_LIBRARY to override this selection or set the CMake environment
# CMAKE_INCLUDE_PATH to modify the search paths.
#
# Note that the header path has changed from SDL2/SDL.h to just SDL.h
# This needed to change because "proper" SDL2 convention
# is #include "SDL.h", not <SDL2/SDL.h>. This is done for portability
# reasons because not all systems place things in SDL2/ (see FreeBSD).
#
# Ported by Johnny Patterson. This is a literal port for SDL2 of the FindSDL.cmake
# module with the minor edit of changing "SDL" to "SDL2" where necessary. This
# was not created for redistribution, and exists temporarily pending official
# SDL2 CMake modules.
# 
# Note that on windows this will only search for the 32bit libraries, to search
# for 64bit change x86/i686-w64 to x64/x86_64-w64

#=============================================================================
# Copyright 2003-2009 Kitware, Inc.
#
# CMake - Cross Platform Makefile Generator
# Copyright 2000-2014 Kitware, Inc.
# Copyright 2000-2011 Insight Software Consortium
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
#
# * Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# * Neither the names of Kitware, Inc., the Insight Software Consortium,
# nor the names of their contributors may be used to endorse or promote
# products derived from this software without specific prior written
# permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# This software is distributed WITHOUT ANY WARRANTY; without even the
# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# See the License for more information.
#=============================================================================
# (To distribute this file outside of CMake, substitute the full
# License text for the above reference.)

FIND_PATH(SDL2_TTF_INCLUDE_DIR SDL_ttf.h
    HINTS
    ${SDL2}
    $ENV{SDL2}
    $ENV{SDL2_TTF}
    PATH_SUFFIXES include/SDL2 include SDL2
    i686-w64-mingw32/include/SDL2
    PATHS
    ~/Library/Frameworks
    /Library/Frameworks
    /usr/local/include/SDL2
    /usr/include/SDL2
    /sw # Fink
    /opt/local # DarwinPorts
    /opt/csw # Blastwave
    /opt
)

# Lookup the 64 bit libs on x64
IF(CMAKE_SIZEOF_VOID_P EQUAL 8)
    FIND_LIBRARY(SDL2_TTF_LIBRARY_TEMP
        NAMES SDL2_ttf
        HINTS
        ${SDL2}
        $ENV{SDL2}
        $ENV{SDL2_TTF}
        PATH_SUFFIXES lib64 lib
        lib/x64
        x86_64-w64-mingw32/lib
        PATHS
        /sw
        /opt/local
        /opt/csw
        /opt
    )
# On 32bit build find the 32bit libs
ELSE(CMAKE_SIZEOF_VOID_P EQUAL 8)
    FIND_LIBRARY(SDL2_TTF_LIBRARY_TEMP
        NAMES SDL2_ttf
        HINTS
        ${SDL2}
        $ENV{SDL2}
        $ENV{SDL2_TTF}
        PATH_SUFFIXES lib
        lib/x86
        i686-w64-mingw32/lib
        PATHS
        /sw
        /opt/local
        /opt/csw
        /opt
    )
ENDIF(CMAKE_SIZEOF_VOID_P EQUAL 8)

SET(SDL2_TTF_FOUND "NO")
    IF(SDL2_TTF_LIBRARY_TEMP)
    # Set the final string here so the GUI reflects the final state.
    SET(SDL2_TTF_LIBRARY ${SDL2_TTF_LIBRARY_TEMP} CACHE STRING "Where the SDL2_ttf Library can be found")
    # Set the temp variable to INTERNAL so it is not seen in the CMake GUI
    SET(SDL2_TTF_LIBRARY_TEMP "${SDL2_TTF_LIBRARY_TEMP}" CACHE INTERNAL "")
    SET(SDL2_TTF_FOUND "YES")
ENDIF(SDL2_TTF_LIBRARY_TEMP)

INCLUDE(FindPackageHandleStandardArgs)

FIND_PACKAGE_HANDLE_STANDARD_ARGS(SDL2_TTF REQUIRED_VARS SDL2_TTF_LIBRARY SDL2_TTF_INCLUDE_DIR)

查找SDL2_image.cmake

# Locate SDL2_image library
# This module defines
# SDL2_IMAGE_LIBRARY, the name of the library to link against
# SDL2_IMAGE_FOUND, if false, do not try to link to SDL2_image
# SDL2_IMAGE_INCLUDE_DIR, where to find SDL_image.h
#
# Additional Note: If you see an empty SDL2_IMAGE_LIBRARY_TEMP in your configuration
# and no SDL2_IMAGE_LIBRARY, it means CMake did not find your SDL2_Image library
# (SDL2_image.dll, libsdl2_image.so, SDL2_image.framework, etc).
# Set SDL2_IMAGE_LIBRARY_TEMP to point to your SDL2 library, and configure again.
# Similarly, if you see an empty SDL2MAIN_LIBRARY, you should set this value
# as appropriate. These values are used to generate the final SDL2_IMAGE_LIBRARY
# variable, but when these values are unset, SDL2_IMAGE_LIBRARY does not get created.
#
# $SDL2 is an environment variable that would
# correspond to the ./configure --prefix=$SDL2
# used in building SDL2.
# l.e.galup 9-20-02
#
# Modified by Eric Wing.
# Added code to assist with automated building by using environmental variables
# and providing a more controlled/consistent search behavior.
# Added new modifications to recognize OS X frameworks and
# additional Unix paths (FreeBSD, etc).
# Also corrected the header search path to follow "proper" SDL2 guidelines.
# Added a search for SDL2main which is needed by some platforms.
# Added a search for threads which is needed by some platforms.
# Added needed compile switches for MinGW.
#
# On OSX, this will prefer the Framework version (if found) over others.
# People will have to manually change the cache values of
# SDL2_IMAGE_LIBRARY to override this selection or set the CMake environment
# CMAKE_INCLUDE_PATH to modify the search paths.
#
# Note that the header path has changed from SDL2/SDL.h to just SDL.h
# This needed to change because "proper" SDL2 convention
# is #include "SDL.h", not <SDL2/SDL.h>. This is done for portability
# reasons because not all systems place things in SDL2/ (see FreeBSD).
#
# Ported by Johnny Patterson. This is a literal port for SDL2 of the FindSDL.cmake
# module with the minor edit of changing "SDL" to "SDL2" where necessary. This
# was not created for redistribution, and exists temporarily pending official
# SDL2 CMake modules.
# 
# Note that on windows this will only search for the 32bit libraries, to search
# for 64bit change x86/i686-w64 to x64/x86_64-w64

#=============================================================================
# Copyright 2003-2009 Kitware, Inc.
#
# CMake - Cross Platform Makefile Generator
# Copyright 2000-2014 Kitware, Inc.
# Copyright 2000-2011 Insight Software Consortium
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
#
# * Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# * Neither the names of Kitware, Inc., the Insight Software Consortium,
# nor the names of their contributors may be used to endorse or promote
# products derived from this software without specific prior written
# permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# This software is distributed WITHOUT ANY WARRANTY; without even the
# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# See the License for more information.
#=============================================================================
# (To distribute this file outside of CMake, substitute the full
# License text for the above reference.)

FIND_PATH(SDL2_IMAGE_INCLUDE_DIR SDL_image.h
    HINTS
    ${SDL2}
    $ENV{SDL2}
    $ENV{SDL2_IMAGE}
    PATH_SUFFIXES include/SDL2 include SDL2
    i686-w64-mingw32/include/SDL2
    x86_64-w64-mingw32/include/SDL2
    PATHS
    ~/Library/Frameworks
    /Library/Frameworks
    /usr/local/include/SDL2
    /usr/include/SDL2
    /sw # Fink
    /opt/local # DarwinPorts
    /opt/csw # Blastwave
    /opt
)

# Lookup the 64 bit libs on x64
IF(CMAKE_SIZEOF_VOID_P EQUAL 8)
    FIND_LIBRARY(SDL2_IMAGE_LIBRARY_TEMP
        NAMES SDL2_image
        HINTS
        ${SDL2}
        $ENV{SDL2}
        $ENV{SDL2_IMAGE}
        PATH_SUFFIXES lib64 lib
        lib/x64
        x86_64-w64-mingw32/lib
        PATHS
        /sw
        /opt/local
        /opt/csw
        /opt
    )
# On 32bit build find the 32bit libs
ELSE(CMAKE_SIZEOF_VOID_P EQUAL 8)
    FIND_LIBRARY(SDL2_IMAGE_LIBRARY_TEMP
        NAMES SDL2_image
        HINTS
        ${SDL2}
        $ENV{SDL2}
        $ENV{SDL2_IMAGE}
        PATH_SUFFIXES lib
        lib/x86
        i686-w64-mingw32/lib
        PATHS
        /sw
        /opt/local
        /opt/csw
        /opt
    )
ENDIF(CMAKE_SIZEOF_VOID_P EQUAL 8)

SET(SDL2_IMAGE_FOUND "NO")
    IF(SDL2_IMAGE_LIBRARY_TEMP)
    # Set the final string here so the GUI reflects the final state.
    SET(SDL2_IMAGE_LIBRARY ${SDL2_IMAGE_LIBRARY_TEMP} CACHE STRING "Where the SDL2_image Library can be found")
    # Set the temp variable to INTERNAL so it is not seen in the CMake GUI
    SET(SDL2_IMAGE_LIBRARY_TEMP "${SDL2_IMAGE_LIBRARY_TEMP}" CACHE INTERNAL "")
    SET(SDL2_IMAGE_FOUND "YES")
ENDIF(SDL2_IMAGE_LIBRARY_TEMP)

INCLUDE(FindPackageHandleStandardArgs)

FIND_PACKAGE_HANDLE_STANDARD_ARGS(SDL2_IMAGE REQUIRED_VARS SDL2_IMAGE_LIBRARY SDL2_IMAGE_INCLUDE_DIR)

以下是makefile，然后是我尝试过的一些不同方法。我已经从makefile中删除了一些不相关的代码以使其更清晰，请查看完整代码on GitHub。

#CPP = clang++
#C = clang
CPP = g++
C = gcc

### Macintosh

LDFLAGS = -L/Library/Frameworks/SDL2.framework \
-L/Library/Frameworks/SDL2_ttf.framework \
-L/Library/Frameworks/SDL2_image.framework \
-lSDL2 -lSDL2_image -lSDL2_ttf
CFLAGS = -I/Library/Frameworks/SDL2.framework/Headers \
-I/Library/Frameworks/SDL2_ttf.framework/Headers \
-I/Library/Frameworks/SDL2_image.framework/Headers \
-Wall -c -std=c89
EXE1 = kiss_example1
EXE2 = kiss_example2

### Linux

#LDFLAGS = -lSDL2 -lSDL2_image -lSDL2_ttf
#CFLAGS = -Wall -c -std=c89
#EXE1 = kiss_example1
#EXE2 = kiss_example2

all: $(EXE1) $(EXE2)

$(EXE1): kiss_example1.o kiss_widgets.o kiss_draw.o kiss_general.o \
kiss_posix.o
    $(C) $^ $(LDFLAGS) -o $@

$(EXE2): kiss_example2.o kiss_widgets.o kiss_draw.o kiss_general.o \
kiss_posix.o
    $(C) $^ $(LDFLAGS) -o $@

kiss_example1.o: kiss_example1.c
    $(C) $(CFLAGS) $^ -o $@

kiss_example2.o: kiss_example2.c
    $(C) $(CFLAGS) $^ -o $@

kiss_widgets.o: kiss_widgets.c
    $(C) $(CFLAGS) $^ -o $@

kiss_draw.o: kiss_draw.c
    $(C) $(CFLAGS) $^ -o $@

kiss_general.o: kiss_general.c
    $(C) $(CFLAGS) $^ -o $@

kiss_posix.o: kiss_posix.c
    $(C) $(CFLAGS) $^ -o $@

clean:
    rm *.o && rm $(EXE1) && rm $(EXE2)
#   del *.o
#   del $(EXE1)
#   del $(EXE2)

LDFLAGS = -framework SDL -framework SDL_ttf -framework SDL_image
CFLAGS = -framework SDL -framework SDL_ttf -framework SDL_image \
-Wall -c -std=c89
EXE1 = kiss_example1
EXE2 = kiss_example2

LDFLAGS = -framework SDL -framework SDL_ttf -framework SDL_image
CFLAGS = -framework SDL -framework SDL_ttf -framework SDL_image \
-I/Library/Frameworks/SDL2.framework/Headers \
-I/Library/Frameworks/SDL2_ttf.framework/Headers \
-I/Library/Frameworks/SDL2_image.framework/Headers \
-Wall -c -std=c89
EXE1 = kiss_example1
EXE2 = kiss_example2

LDFLAGS = -framework SDL -framework SDL_ttf -framework SDL_image
CFLAGS = -Wall -c -std=c89
EXE1 = kiss_example1
EXE2 = kiss_example2

我正在尝试构建的完整项目是 KISS_SDL，可以在 on GitHub 找到。

【问题讨论】：

首先要检查 - 应该包含哪个目录，以便使 #include <SDL2/SDL.h> 工作。尝试在*_INCLUDE_DIR变量中指定的目录下找到这个文件。
@usr1234567 它是特定于 OSX 操作环境的；你确定不应该使用它吗？精通 Make 但仅在 Windows 上的人可能无法回答这个问题。同样，没有使用过 Make，但对 OSX Framework Bundles 了如指掌的人可能会发现命名或其他方面的简单错误。
@usr1234567 啊，我明白了，谢谢你指出这一点。

标签： makefile cmake sdl-2

【解决方案1】：

CMake 和 make 的用途完全不同，尽管相关。 CMake根据各种CMakeLists.txt文件给出的要求分析运行它的系统，并构造一个Makefile。然后通过make 执行实际构建。 CMake 的作用类似于传统的configure 脚本，尤其是GNU Autoconf 生成的配置脚本。

那么CMake 如何发现 SDL2 标头的位置？它在系统某处有一个小脚本，知道如何去做。实际上有几个。（其中数百个包含在 CMake 安装中，软件分销商也可以提供自己的。）它可能使用 pkg-config，正如另一个答案建议你自己做的那样，或者它可能会测试几个常见位置，或者它可能使用其他一些设施。您的 CMakeLists.txt 调用其中三个并指示 CMake 如何使用这些行的结果：

find_package(SDL2 REQUIRED)
include_directories(${SDL2_INCLUDE_DIR})

find_package(SDL2_ttf REQUIRED)
include_directories(${SDL2_TTF_INCLUDE_DIR})

find_package(SDL2_image REQUIRED)
include_directories(${SDL2_IMAGE_INCLUDE_DIR})

您可能可以通过检查相应的 cmake 脚本来确定 CMake 实际在做什么。在我的 Linux 系统上，它们会是

/usr/share/cmake/Modules/FindSDL.cmake
/usr/share/cmake/Modules/FindSDL_ttf.cmake
/usr/share/cmake/Modules/FindSDL_image.cmake

您在 Mac 上的哪个位置可以找到它们取决于 CMake 的安装方式的详细信息。

或者，您可以检查由CMake 生成的Makefile。它会比你的复杂得多，但你应该能够确定哪些标志被传递给编译器和链接器。

【讨论】：

感谢您的评论！事实上，CMake 之所以能够找到 SDL2，是因为我在 /cmake 目录中包含了 FindSDL2.cmake 文件。这些是我在互联网上找到的文件（我认为来自 lazyfoo.net/tutorials/SDL/index.php ）。我已经检查了所有三个，以及 CMake 生成的 makefile，但是我仍然不确定我做错了什么。如果您或其他人想查看它们，我会将 .cmake 文件添加到我的答案中，但我认为问题更多在于我对 Make 的缺乏经验，而不是 CMake 的一些魔法。不过，我会再看看。谢谢

【解决方案2】：

原因在您显示的每个FindSDL*.cmake 脚本中都以注释形式写入：

请注意，标头路径已从 SDL2/SDL.h 更改为仅 SDL.h

您可能使用了来自不兼容版本的库 SDL 和 SDL_ttf 的标头：第一个提供主标头为 SDL.h，但第二个预计它是 SDL2/SDL2.h。

【讨论】：

感谢您的评论！我考虑过这一点，但由于一切都适用于 CMake，我不确定这些库是否不兼容。 CMake 可能会做一些奇怪的事情，比如复制库以创建新的文件结构，但如果是这样的话，我肯定也可以用 Make 来做吗？我会仔细检查是否有新的库版本。
@MichaelBethke：不，CMake 从不做奇怪的事情。尤其是你所描述的那些奇怪的事情。使用 VERBOSE=1 运行 CMake 生成的 make 文件以接听电话。然后你可以将它与你自己的 make 文件进行比较。

【解决方案3】：

我通常使用pkg-config 来发现头文件和库位置。这应该使用GNU make：

SDL2_CXXFLAGS := \
    $(shell pkg-config sdl2 --cflags) \
    $(shell pkg-config SDL2_ttf --cflags) \
    $(shell pkg-config SDL2_image --cflags)

SDL2_LDFLAGS := \
    $(shell pkg-config sdl2 --libs) \
    $(shell pkg-config SDL2_ttf --libs) \
    $(shell pkg-config SDL2_image --libs)

我没有在Windows 上使用过pkg-config，但显然它是可用的。

【讨论】：

【解决方案4】：

我在使用 SDL2 时遇到了类似的问题，我按照这些答案中的说明解决了这个问题：

On mac, g++ (clang) fails to search /usr/local/include and /usr/local/lib by default

出于某种原因，OSX 似乎默认覆盖了 include 和 lib 路径。

【讨论】：

使用该问题中提供的答案（安装重复的 Xcode 命令行工具），我可以使用我的原始 Makefile，稍作修改，构建项目。非常感谢你的帮助。但是，CMake 能够在没有这个的情况下构建项目，所以我想寻求一个不需要其他开发人员完成这个额外步骤的解决方案。不过，我真的很感谢你的回答，谢谢！
我并不真正使用 CMake，但据我了解，它会生成某种构建脚本或 Makefile。你可以看看那些，看看他们用的是什么魔法酱。我怀疑他们会在多个位置查找库和包含，然后使用第一个有效的位置。

【解决方案5】：

这是编写 makefile 的一种方法：

由于您的 makefile 被命名为 kiss_makefile，因此以下 make 文件将通过以下方式执行：

make -f kiss_makefile

现在是 makefile 的内容：

CPP := /bin/g++
C   := /bin/gcc
RM  := /bin/rm


C_FLAGS_32 := -D32_BIT \
    -IC:\SDL2-2.0.4\include \
    -IC:\SDL2-2.0.4\i686-w64-mingw32\include \
    -IC:\SDL2_ttf-2.0.14\i686-w64-mingw32\include \
    -IC:\SDL2_image-2.0.1\i686-w64-mingw32\include \
    -Wall -Wextra -Wconversion -pedantic -c -std=gnu99 -m32 -march=i686

C_FLAGS_64 := -D64_BIT \
    -IC:\SDL2-2.0.4\x86_64-w64-mingw32\include \
    -IC:\SDL2_ttf-2.0.14\x86_64-w64-mingw32\include \
    -IC:\SDL2_image-2.0.1\x86_64-w64-mingw32\include \
    -Wall -Wextra -Wconversion -pedantic -c -std=gnu99

L_FLAGS_32 := \
    -LC:\SDL2-2.0.4\x86_64-w64-mingw32\lib \
    -LC:\SDL2_ttf-2.0.14\x86_64-w64-mingw32\lib \
    -LC:\SDL2_image-2.0.1\x86_64-w64-mingw32\lib \
    -lmingw32 -lSDL2main -lSDL2 -lSDL2_image -lSDL2_ttf \
    -mwindows

L_FLAGS_64 := \
    -LC:\SDL2-2.0.4\x86_64-w64-mingw32\lib \
    -LC:\SDL2_ttf-2.0.14\x86_64-w64-mingw32\lib \
    -LC:\SDL2_image-2.0.1\x86_64-w64-mingw32\lib \
    -lmingw32 -lSDL2main -lSDL2 -lSDL2_image -lSDL2_ttf \
    -mwindows

ARCH := $(shell getconf LONG_BIT)

CFLAGS := C_FLAGS_$(ARCH)

LFLAGS := L_FLAGS_$(ARCH)

SRC1 := kiss_example1.c kiss_widgets.c kiss_draw.c kiss_general.o kiss_posix.c
OBJ1 := $(SRC1:.c=.o)

SRC2 := kiss_example2.c kiss_widgets.c kiss_draw.c kiss_general.o kiss_posix.c
OBJ2 := $(SRC2:.c=.o)

.PHONY: all
all: $(EXE1) $(EXE2)

$(EXE1): $(OBJ1)
<tab>$(C) $^  -o $@ $(LDFLAGS)

$(EXE2): $(OBJ2)
<tab>$(C) $^  -o $@ $(LDFLAGS)

%.o:%.c
<tab>$(C) $(CFLAGS) $< -o $@


.PHONY: clean
clean:
<tab>rm *.o
<tab>rm $(EXE1)
<tab>rm $(EXE2)

注意make 的正确指示某些目标：all 和 clean 不会生成同名文件

注意将每个源文件编译成目标文件的通用规则/配方。

注意：C、RM 和 CPP 三个宏的原因是执行该名称的正确文件。因此，这些宏包含正确文件的路径。

请注意编译参数-D32_BIT 和-D64_BIT 是您可以使用的，如果源代码需要执行不同的操作，具体取决于底层架构。

注意答案是<tab>，在实际的makefile中，用实际的制表符替换

【讨论】：

感谢您的回答！对不起，我什至可能对 Make 了解不够，无法正确使用您的代码，但我用这个替换了我的 Kiss_makefile，现在使用 make -f kiss_makefile 返回 make: Nothing to be done for 'all'。我应该尝试以某种方式合并这两个文件吗？
'all' 目标表示要生成两个可执行文件。如果自上次生成可执行文件以来源文件/头文件中的任何内容都没有更新，那么“自然”就没有什么可做的了。您可以尝试对其中一个源文件进行一些编辑，然后相关的工作将由“make”重新完成。我希望您确实知道“制造”设施是为了避免重复不必要的操作。回到编译可能需要数小时和数小时的时候，“make”工具是天赐之物。今天，它更多地用于组织所有需要的操作以实现可重复性。
我知道通常当 Make 说没有什么可做的时候，没有要构建的更改，但是在这种情况下，它没有构建任何东西。看起来您可能在所有这些中都针对 MinGW，所以也许这个 Makefile 是专门为 Windows 编写的（我没有使用 Windows，所以也许可以解释一下）？对不起，我还在努力学习Make，所以请原谅我的无知。谢谢！