Makefile specified in this question, compiling all the cpp programs in a folder but not with python embedded cpp programs.
all: myUB
sourcesC := $(wildcard ../src/*.cpp)
objectsC := $(patsubst %.cpp,%.o,$(sourcesC))
INPATH=-I"C:/Python27/include"
LIBPATH=-L"C:/Python27/libs"-lpython27
myUB:
#echo 'Building target $#'
g++ -O0 -Wall -c -g3 -fmessage-length=0 \
$(sourcesC)
del *.o
clean:
Your final makefile could look somthing like:
all: myUB
sourcesC := $(wildcard ../src/*.cpp)
# Not used
#objectsC := $(patsubst %.cpp,%.o,$(sourcesC))
INC = -IC:\Python27\include
LIBS = -LC:\Python27\libs -lpython27
myUB:
#echo 'Building target $#'
g++ -O0 -Wall -g3 -fmessage-length=0 -o myprog.out $(sourcesC) $(INC) $(LIBS)
clean:
rm myprog.out
update
For the undefined ref to WinMain(), it means the linker can't find this function in your code. Either you need to include a library/object that contains it or you can define it yourself in a cpp file like:
#include <windows.h>
int WINAPI (*MyDummyReferenceToWinMain)(HINSTANCE hInstance, ..., int
nShowCmd ) = &WinMain;
I got the function template from here.
But this seems to mean that you are creating a windows application instead of a console app which uses int main(...) entry point.
Update2
I have made a new makefile to do what you have asked for in your latest comment which seems to be to create one executable per source file - I am assuming each source file has its own main.
# Build vars
CXX = g++
CXX_FLAGS = -O0 -Wall -g3
INC = -IC:\Python27\includ
LIBS = -LC:\Python27\libs -lpython27
# Sources
SRC_DIR=src
SOURCES = $(wildcard $(SRC_DIR)/*.cpp)
$(info SOURCES: $(SOURCES))
# Executables
EXE_DIR=bin
EXECUTABLES = $(subst $(SRC_DIR)/,$(EXE_DIR)/,$(subst cpp,out,$(SOURCES)))
$(info EXECUTABLES: $(EXECUTABLES))
$(info ----)
# Directories
DIRS = $(EXE_DIR)
# Rule to create folders and compile executables
all: $(DIRS) $(EXECUTABLES)
# Pattern rule to build each executable
$(EXE_DIR)/%.out : $(SRC_DIR)/%.cpp
#echo "compiling $< --> $#"
#$(CXX) $(CXX_FLAGS) -o $# $< $(INC) $(LIBS)
# Rule to create output dirs
$(DIRS):
#echo "Creating output folders"
#mkdir -p $(EXE_DIR)
# Rule to clean up
clean:
#echo "Cleaning"
#rm -rf $(EXE_DIR)
This should create one executable in the folder bin/ for each source file (.cpp) in folder src/.
I searched on the inet but I did not find any clear answer. Could you point me in the right direction on how to convert a Makefile into a CMakeLists?
I want to do that because I am new both to makefile and to cmake. In my job CMake is more used and since I need to start using one of them I prefer having everything in CMake. I know CMake is generating a Makefile but for me CMake is way easier to read than a Makefile.
I have the following Makefile:
PREFIX ?= /usr/local
CC = gcc
AR = ar
CFLAGS = -std=gnu99 -fPIC -Wall -Wno-unused-parameter -Wno-unused-function -I. -O4
APRILTAG_SRCS := $(shell ls *.c common/*.c)
APRILTAG_HEADERS := $(shell ls *.h common/*.h)
APRILTAG_OBJS := $(APRILTAG_SRCS:%.c=%.o)
TARGETS := libapriltag.a libapriltag.so
# LIBS := -Lusr/include/flycapture
.PHONY: all
all: $(TARGETS)
#$(MAKE) -C example all
.PHONY: install
install: libapriltag.so
#chmod +x install.sh
#./install.sh $(PREFIX)/lib libapriltag.so #this should be the line that install the library
#./install.sh $(PREFIX)/include/apriltag $(APRILTAG_HEADERS)
#sed 's:^prefix=$$:prefix=$(PREFIX):' < apriltag.pc.in > apriltag.pc
#./install.sh $(PREFIX)/lib/pkgconfig apriltag.pc
#rm apriltag.pc
#ldconfig
libapriltag.a: $(APRILTAG_OBJS)
#echo " [$#]"
#$(AR) -cq $# $(APRILTAG_OBJS)
libapriltag.so: $(APRILTAG_OBJS)
#echo " [$#]"
#$(CC) -fPIC -shared -o $# $^
%.o: %.c
#echo " $#"
#$(CC) -o $# -c $< $(CFLAGS)
.PHONY: clean
clean:
#rm -rf *.o common/*.o $(TARGETS)
#$(MAKE) -C example clean
I am not asking you to do my job but I would like to have some kind of guide or a good link where to look.
The project contains both C and C++ programming languages.
I started creating a new CMakeLists.txt file, but it is still not working. It gives me the following errors:
You have called ADD_LIBRARY for library librapriltag.a without any source files. This typically indicates a problem with your CMakeLists.txt file
-- Configuring done
CMake Error: Cannot determine link language for target "librapriltag.a".
CMake Error: CMake can not determine linker language for target: librapriltag.a
-- Generating done
-- Build files have been written to: .....
The CMakeLists.txt I started creating is the following:
project( apriltag2 C CXX)
cmake_minimum_required(VERSION 2.8)
set(CMAKE_C_FLAGS "-std=gnu99 -fPIC -Wall -Wno-unused-parameter -Wno-unused-function -I. -O4")
include_directories("/home/fschiano/Repositories/apriltag2")
include_directories("/home/fschiano/Repositories/apriltag2/common")
add_library( librapriltag.a )
The CMakeLists.txt which works is the following:
project( apriltag2 )
cmake_minimum_required(VERSION 2.8)
set(CMAKE_C_FLAGS "-std=gnu99 -fPIC -Wall -Wno-unused-parameter -Wno-unused-function -I. -O4")
message("CMAKE_SOURCE_DIR=${CMAKE_SOURCE_DIR}")
file(GLOB apriltag_SRC "*.c")
file(GLOB apriltag_HEADERS "*.h")
set(APRILTAG_SRCS ${apriltag_SRC})
set(APRILTAG_HEADERS ${apriltag_HEADERS})
message(STATUS "CMAKE_CURRENT_LIST_DIR=${CMAKE_CURRENT_LIST_DIR}")
add_library(apriltag STATIC ${APRILTAG_SRCS})
target_include_directories(apriltag PUBLIC ${CMAKE_SOURCE_DIR})
target_compile_options(apriltag PUBLIC -fPIC -Wall -Wno-unused-parameter -Wno-unused-function -O4)
install(TARGETS apriltag
ARCHIVE DESTINATION lib
RUNTIME DESTINATION bin
LIBRARY DESTINATION lib)
install(DIRECTORY CMAKE_CURRENT_LIST_DIR/include/
DESTINATION CMAKE_CURRENT_LIST_DIR/include/
FILES_MATCHING PATTERN *.h)
EDIT:
Something is still not right. If I want to change something in my library, like something which is in /home/fschiano/Repositories/apriltag2/common
If I use the Makefile which I had before doing all these modifications and I do:
make
do some modifications in the files I wanted to modify
sudo make install, which would give me the following output:
/usr/local/lib/libapriltag.so
/usr/local/include/apriltag/apriltag.h
/usr/local/include/apriltag/common/g2d.h
/usr/local/include/apriltag/common/getopt.h
/usr/local/include/apriltag/common/homography.h
/usr/local/include/apriltag/common/image_f32.h
/usr/local/include/apriltag/common/image_u8.h
/usr/local/include/apriltag/common/image_u8x3.h
/usr/local/include/apriltag/common/matd.h
/usr/local/include/apriltag/common/math_util.h
/usr/local/include/apriltag/common/pnm.h
/usr/local/include/apriltag/common/postscript_utils.h
/usr/local/include/apriltag/common/string_util.h
/usr/local/include/apriltag/common/svd22.h
/usr/local/include/apriltag/common/thash_impl.h
/usr/local/include/apriltag/common/timeprofile.h
/usr/local/include/apriltag/common/time_util.h
/usr/local/include/apriltag/common/unionfind.h
/usr/local/include/apriltag/common/workerpool.h
/usr/local/include/apriltag/common/zarray.h
/usr/local/include/apriltag/common/zhash.h
/usr/local/include/apriltag/common/zmaxheap.h
/usr/local/include/apriltag/tag16h5.h
/usr/local/include/apriltag/tag25h7.h
/usr/local/include/apriltag/tag25h9.h
/usr/local/include/apriltag/tag36artoolkit.h
/usr/local/include/apriltag/tag36h10.h
/usr/local/include/apriltag/tag36h11.h
/usr/local/lib/pkgconfig/apriltag.pc
/sbin/ldconfig.real: /usr/lib/libstdc++.so.5 is not a symbolic link
and the modifications would take effect.
Now, if I remove the Makefile and I do:
cmake .
make
do some modifications in the files I wanted to modify
sudo make install, it gives me the following output:
Install the project...
-- Install configuration: ""
-- Up-to-date: /usr/local/lib/libapriltag.a
So it seems that the install part of the CMakeLists.txt is not right!
The file install.sh is the following.
#!/bin/sh -e
# Usage: install.sh TARGET [RELATIVE PATHS ...]
#
# e.g. ./install.sh /usr/local foo/file1 foo/file2 ...
# This creates the files /usr/local/foo/file1 and /usr/local/foo/file2
TARGETDIR=$1
shift
for src in "$#"; do
dest=$TARGETDIR/$src
mkdir -p $(dirname $dest)
cp $src $dest
echo $dest
done
Could you try to help me?
Thanks
Let's go through that step-by-step:
PREFIX ?= /usr/local
We ignore that, as it's the default. Can be overwritten by CMAKE_INSTALL_PREFIX.
CC = gcc
AR = ar
Ignore these as well. Use CMAKE_C_COMPILER and CMAKE_CXX_COMPILER to forcibly switch the compiler.
CFLAGS = -std=gnu99 -fPIC -Wall -Wno-unused-parameter -Wno-unused-function -I. -O4
They are pretty special for gcc-like compilers. Set them conditionally for CMAKE_C_COMPILER_ID MATCHES GNU further down after defining the target.
The standard is set by set(C_STANDARD 98) and set(CXX_STANDARD 98).
APRILTAG_SRCS := $(shell ls *.c common/*.c)
Define a variable listing all the source files individually: set(APRILTAG_SRCS ...)
APRILTAG_HEADERS := $(shell ls *.h common/*.h)
Define a variable listing all the header file individually: set(APRILTAG_HEADERS ...). However, you don't really need them anywhere (unless you want Visual Studio to list them).
APRILTAG_OBJS := $(APRILTAG_SRCS:%.c=%.o)
In most cases, you don't need that. For those rare cases there are Object Libraries.
TARGETS := libapriltag.a libapriltag.so
# LIBS := -Lusr/include/flycapture
We define our libraries here with add_library:
add_library(apriltag ${APRILTAG_SRCS})
target_include_directories(apriltag PUBLIC ${CMAKE_CURRENT_LIST_DIR}/include/apriltag)
target_compile_options(apriltag PUBLIC -fPIC -Wall -Wno-unused-parameter -Wno-unused-function -O4)
The switch between static and shared is done via BUILD_SHARED_LIBS on invocation of CMake.
.PHONY: all
all: $(TARGETS)
#$(MAKE) -C example all
Nothing to do here. CMake will automatically create that.
.PHONY: install
install: libapriltag.so
#chmod +x install.sh
#./install.sh $(PREFIX)/lib libapriltag.so #this should be the line that install the library
#./install.sh $(PREFIX)/include/apriltag $(APRILTAG_HEADERS)
#sed 's:^prefix=$$:prefix=$(PREFIX):' < apriltag.pc.in > apriltag.pc
#./install.sh $(PREFIX)/lib/pkgconfig apriltag.pc
#rm apriltag.pc
#ldconfig
CMake will ease this up by a magnitude:
install(TARGETS apriltag
ARCHIVE DESTINATION lib
RUNTIME DESTINATION bin
LIBRARY DESTINATION lib)
install(DIRECTORY include/
DESTINATION include/
FILES_MATCHING PATTERN *.h)
That will install the library static and shared library (whatever exists) and the header files.
libapriltag.a: $(APRILTAG_OBJS)
#echo " [$#]"
#$(AR) -cq $# $(APRILTAG_OBJS)
libapriltag.so: $(APRILTAG_OBJS)
#echo " [$#]"
#$(CC) -fPIC -shared -o $# $^
%.o: %.c
#echo " $#"
#$(CC) -o $# -c $< $(CFLAGS)
All this is not needed.
.PHONY: clean
clean:
#rm -rf *.o common/*.o $(TARGETS)
#$(MAKE) -C example clean
You don't need that. CMake will generate a clean target automatically.
Judging from TARGETS := libapriltag.a libapriltag.so, you'll defintely need add_library command to create targets.
Instead of gathering souces to be compiled using wildcards like APRILTAG_SRCS := $(shell ls *.c common/*.c) it is recommended to list them explicitly in add_library call. But if you really want to list them automatically, see file(GLOB ...) command. (There are some important things to be aware of, though, see Specify source files globally with GLOB?).
The clean target would be generated automatically by CMake.
Finally, see the documentation for install() command to create install rules.
Compiler flags are set using set(CMAKE_C_FLAGS "blabla"), or appended using set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} blabla").
I'm trying to migrate an existing C/C++ CUDA project into Nsight Eclipse. I'm using a manually written makefile to build the project, however I am getting the following error:
#error -- unsupported GNU version! gcc versions later than 4.9 are not supported!
I previously had this error when I was using just a makefile outside of Nsight, however I fixed it by creating symlinks to gcc-4.9 and g++-4.9 in /usr/local/cuda-7.5/bin. This does not work for Nsight.
Here is my makefile (NOTE: I've set the CUDA_HOME environment variable inside Nsight):
NVCC := nvcc
MODULES := FA_kernels FD_kernels MEM_kernels MOD_kernels .
SRC_DIR := $(MODULES)
BUILD_DIR := $(addprefix build/,$(MODULES))
SRC := $(foreach sdir,$(SRC_DIR),$(wildcard $(sdir)/*.cu))
OBJ := $(patsubst %.cu,build/%.o,$(SRC))
HEADERS := headers $(CUDA_HOME)/include $(CUDA_HOME)/samples/common/inc
INCLUDES := $(addprefix -I,$(HEADERS))
build/%.o: %.cu
$(NVCC) $(INCLUDES) -c $< -o $#
.PHONY: all checkdirs clean
all: checkdirs build/lem
build/lem: $(OBJ)
$(NVCC) $^ -o $# -lgdal
checkdirs: $(BUILD_DIR)
$(BUILD_DIR):
#mkdir -p $#
clean:
#rm -rf build
Is there a way I can force Nsight to use gcc-4.9 and g++-4.9?
I assume based on your question text you have imported this as a makefile project.
In that case, one option would be to change the first line in your makefile to something like this:
NVCC := nvcc -ccbin /path/to/gcc
You can read more about this option in the nvcc documentation
This would effect this change just for this project/makefile, not for all projects or all of eclipse/nsight
I routinely work on several different computers and several different operating systems, which are Mac OS X, Linux, or Solaris. For the project I'm working on, I pull my code from a remote git repository.
I like to be able to work on my projects regardless of which terminal I'm at. So far, I've found ways to get around the OS changes by changing the makefile every time I switch computers. However, this is tedious and causes a bunch of headaches.
How can I modify my makefile so that it detects which OS I'm using and modifies syntax accordingly?
Here is the makefile:
cc = gcc -g
CC = g++ -g
yacc=$(YACC)
lex=$(FLEX)
all: assembler
assembler: y.tab.o lex.yy.o
$(CC) -o assembler y.tab.o lex.yy.o -ll -l y
assembler.o: assembler.c
$(cc) -o assembler.o assembler.c
y.tab.o: assem.y
$(yacc) -d assem.y
$(CC) -c y.tab.c
lex.yy.o: assem.l
$(lex) assem.l
$(cc) -c lex.yy.c
clean:
rm -f lex.yy.c y.tab.c y.tab.h assembler *.o *.tmp *.debug *.acts
There are many good answers here already, but I wanted to share a more complete example that both:
doesn't assume uname exists on Windows
also detects the processor
The CCFLAGS defined here aren't necessarily recommended or ideal; they're just what the project to which I was adding OS/CPU auto-detection happened to be using.
ifeq ($(OS),Windows_NT)
CCFLAGS += -D WIN32
ifeq ($(PROCESSOR_ARCHITEW6432),AMD64)
CCFLAGS += -D AMD64
else
ifeq ($(PROCESSOR_ARCHITECTURE),AMD64)
CCFLAGS += -D AMD64
endif
ifeq ($(PROCESSOR_ARCHITECTURE),x86)
CCFLAGS += -D IA32
endif
endif
else
UNAME_S := $(shell uname -s)
ifeq ($(UNAME_S),Linux)
CCFLAGS += -D LINUX
endif
ifeq ($(UNAME_S),Darwin)
CCFLAGS += -D OSX
endif
UNAME_P := $(shell uname -p)
ifeq ($(UNAME_P),x86_64)
CCFLAGS += -D AMD64
endif
ifneq ($(filter %86,$(UNAME_P)),)
CCFLAGS += -D IA32
endif
ifneq ($(filter arm%,$(UNAME_P)),)
CCFLAGS += -D ARM
endif
endif
The uname command (http://developer.apple.com/documentation/Darwin/Reference/ManPages/man1/uname.1.html) with no parameters should tell you the operating system name. I'd use that, then make conditionals based on the return value.
Example
UNAME := $(shell uname)
ifeq ($(UNAME), Linux)
# do something Linux-y
endif
ifeq ($(UNAME), Solaris)
# do something Solaris-y
endif
Detect the operating system using two simple tricks:
First the environment variable OS
Then the uname command
ifeq ($(OS),Windows_NT) # is Windows_NT on XP, 2000, 7, Vista, 10...
detected_OS := Windows
else
detected_OS := $(shell uname) # same as "uname -s"
endif
Or a more safe way, if not on Windows and uname unavailable:
ifeq ($(OS),Windows_NT)
detected_OS := Windows
else
detected_OS := $(shell sh -c 'uname 2>/dev/null || echo Unknown')
endif
Ken Jackson proposes an interesting alternative if you want to distinguish Cygwin/MinGW/MSYS/Windows. See his answer that looks like that:
ifeq '$(findstring ;,$(PATH))' ';'
detected_OS := Windows
else
detected_OS := $(shell uname 2>/dev/null || echo Unknown)
detected_OS := $(patsubst CYGWIN%,Cygwin,$(detected_OS))
detected_OS := $(patsubst MSYS%,MSYS,$(detected_OS))
detected_OS := $(patsubst MINGW%,MSYS,$(detected_OS))
endif
Then you can select the relevant stuff depending on detected_OS:
ifeq ($(detected_OS),Windows)
CFLAGS += -D WIN32
endif
ifeq ($(detected_OS),Darwin) # Mac OS X
CFLAGS += -D OSX
endif
ifeq ($(detected_OS),Linux)
CFLAGS += -D LINUX
endif
ifeq ($(detected_OS),GNU) # Debian GNU Hurd
CFLAGS += -D GNU_HURD
endif
ifeq ($(detected_OS),GNU/kFreeBSD) # Debian kFreeBSD
CFLAGS += -D GNU_kFreeBSD
endif
ifeq ($(detected_OS),FreeBSD)
CFLAGS += -D FreeBSD
endif
ifeq ($(detected_OS),NetBSD)
CFLAGS += -D NetBSD
endif
ifeq ($(detected_OS),DragonFly)
CFLAGS += -D DragonFly
endif
ifeq ($(detected_OS),Haiku)
CFLAGS += -D Haiku
endif
Notes:
Command uname is same as uname -s because option -s (--kernel-name) is the default. See why uname -s is better than uname -o.
The use of OS (instead of uname) simplifies the identification algorithm. You can still use solely uname, but you have to deal with if/else blocks to check all MinGW, Cygwin, etc. variations.
The environment variable OS is always set to "Windows_NT" on different Windows versions (see %OS% environment variable on Wikipedia).
An alternative of OS is the environment variable MSVC (it checks the presence of MS Visual Studio, see example using Visual C++).
Below I provide a complete example using make and gcc to build a shared library: *.so or *.dll depending on the platform. The example is as simplest as possible to be more understandable.
To install make and gcc on Windows see Cygwin or MinGW.
My example is based on five files
├── lib
│ └── Makefile
│ └── hello.h
│ └── hello.c
└── app
└── Makefile
└── main.c
Reminder: Makefile is indented using tabulation. Caution when copy-pasting below sample files.
The two Makefile files
1. lib/Makefile
ifeq ($(OS),Windows_NT)
uname_S := Windows
else
uname_S := $(shell uname -s)
endif
ifeq ($(uname_S), Windows)
target = hello.dll
endif
ifeq ($(uname_S), Linux)
target = libhello.so
endif
#ifeq ($(uname_S), .....) #See https://stackoverflow.com/a/27776822/938111
# target = .....
#endif
%.o: %.c
gcc -c $< -fPIC -o $#
# -c $< => $< is first file after ':' => Compile hello.c
# -fPIC => Position-Independent Code (required for shared lib)
# -o $# => $# is the target => Output file (-o) is hello.o
$(target): hello.o
gcc $^ -shared -o $#
# $^ => $^ expand to all prerequisites (after ':') => hello.o
# -shared => Generate shared library
# -o $# => Output file (-o) is $# (libhello.so or hello.dll)
2. app/Makefile
ifeq ($(OS),Windows_NT)
uname_S := Windows
else
uname_S := $(shell uname -s)
endif
ifeq ($(uname_S), Windows)
target = app.exe
endif
ifeq ($(uname_S), Linux)
target = app
endif
#ifeq ($(uname_S), .....) #See https://stackoverflow.com/a/27776822/938111
# target = .....
#endif
%.o: %.c
gcc -c $< -I ../lib -o $#
# -c $< => compile (-c) $< (first file after :) = main.c
# -I ../lib => search headers (*.h) in directory ../lib
# -o $# => output file (-o) is $# (target) = main.o
$(target): main.o
gcc $^ -L../lib -lhello -o $#
# $^ => $^ (all files after the :) = main.o (here only one file)
# -L../lib => look for libraries in directory ../lib
# -lhello => use shared library hello (libhello.so or hello.dll)
# -o $# => output file (-o) is $# (target) = "app.exe" or "app"
To learn more, read Automatic Variables documentation as pointed out by cfi.
The source code
- lib/hello.h
#ifndef HELLO_H_
#define HELLO_H_
const char* hello();
#endif
- lib/hello.c
#include "hello.h"
const char* hello()
{
return "hello";
}
- app/main.c
#include "hello.h" //hello()
#include <stdio.h> //puts()
int main()
{
const char* str = hello();
puts(str);
}
The build
Fix the copy-paste of Makefile (replace leading spaces by one tabulation).
> sed 's/^ */\t/' -i */Makefile
The make command is the same on both platforms. The given output is on Unix-like OSes:
> make -C lib
make: Entering directory '/tmp/lib'
gcc -c hello.c -fPIC -o hello.o
# -c hello.c => hello.c is first file after ':' => Compile hello.c
# -fPIC => Position-Independent Code (required for shared lib)
# -o hello.o => hello.o is the target => Output file (-o) is hello.o
gcc hello.o -shared -o libhello.so
# hello.o => hello.o is the first after ':' => Link hello.o
# -shared => Generate shared library
# -o libhello.so => Output file (-o) is libhello.so (libhello.so or hello.dll)
make: Leaving directory '/tmp/lib'
> make -C app
make: Entering directory '/tmp/app'
gcc -c main.c -I ../lib -o main.o
# -c main.c => compile (-c) main.c (first file after :) = main.cpp
# -I ../lib => search headers (*.h) in directory ../lib
# -o main.o => output file (-o) is main.o (target) = main.o
gcc main.o -L../lib -lhello -o app
# main.o => main.o (all files after the :) = main.o (here only one file)
# -L../lib => look for libraries in directory ../lib
# -lhello => use shared library hello (libhello.so or hello.dll)
# -o app => output file (-o) is app.exe (target) = "app.exe" or "app"
make: Leaving directory '/tmp/app'
The run
The application requires to know where is the shared library.
On Windows, a simple solution is to copy the library where the application is:
> cp -v lib/hello.dll app
`lib/hello.dll' -> `app/hello.dll'
On Unix-like OSes, you can use the LD_LIBRARY_PATH environment variable:
> export LD_LIBRARY_PATH=lib
Run the command on Windows:
> app/app.exe
hello
Run the command on Unix-like OSes:
> app/app
hello
I was recently experimenting in order to answer this question I was asking myself. Here are my conclusions:
Since in Windows, you can't be sure that the uname command is available, you can use gcc -dumpmachine. This will display the compiler target.
There may be also a problem when using uname if you want to do some cross-compilation.
Here's a example list of possible output of gcc -dumpmachine:
mingw32
i686-pc-cygwin
x86_64-redhat-linux
You can check the result in the makefile like this:
SYS := $(shell gcc -dumpmachine)
ifneq (, $(findstring linux, $(SYS)))
# Do Linux things
else ifneq(, $(findstring mingw, $(SYS)))
# Do MinGW things
else ifneq(, $(findstring cygwin, $(SYS)))
# Do Cygwin things
else
# Do things for others
endif
It worked well for me, but I'm not sure it's a reliable way of getting the system type. At least it's reliable about MinGW and that's all I need since it does not require to have the uname command or MSYS package in Windows.
To sum up, uname gives you the system on which you're compiling, and gcc -dumpmachine gives you the system for which you are compiling.
The git makefile contains numerous examples of how to manage without autoconf/automake, yet still work on a multitude of unixy platforms.
Update: I now consider this answer to be obsolete. I posted a new perfect solution further down.
If your makefile may be running on non-Cygwin Windows, uname may not be available. That's awkward, but this is a potential solution. You have to check for Cygwin first to rule it out, because it has WINDOWS in its PATH environment variable too.
ifneq (,$(findstring /cygdrive/,$(PATH)))
UNAME := Cygwin
else
ifneq (,$(findstring WINDOWS,$(PATH)))
UNAME := Windows
else
UNAME := $(shell uname -s)
endif
endif
That's the job that GNU's automake/autoconf are designed to solve. You might want to investigate them.
Alternatively you can set environment variables on your different platforms and make you Makefile conditional against them.
I ran into this problem today and I needed it on Solaris so here is a POSIX standard way to do (something very close to) this.
#Detect OS
UNAME = `uname`
# Build based on OS name
DetectOS:
-#make $(UNAME)
# OS is Linux, use GCC
Linux: program.c
#SHELL_VARIABLE="-D_LINUX_STUFF_HERE_"
rm -f program
gcc $(SHELL_VARIABLE) -o program program.c
# OS is Solaris, use c99
SunOS: program.c
#SHELL_VARIABLE="-D_SOLARIS_STUFF_HERE_"
rm -f program
c99 $(SHELL_VARIABLE) -o program program.c
I finally found the perfect solution that solves this problem for me.
ifeq '$(findstring ;,$(PATH))' ';'
UNAME := Windows
else
UNAME := $(shell uname 2>/dev/null || echo Unknown)
UNAME := $(patsubst CYGWIN%,Cygwin,$(UNAME))
UNAME := $(patsubst MSYS%,MSYS,$(UNAME))
UNAME := $(patsubst MINGW%,MSYS,$(UNAME))
endif
The UNAME variable is set to Linux, Cygwin, MSYS, Windows, FreeBSD, NetBSD (or presumably Solaris, Darwin, OpenBSD, AIX, HP-UX), or Unknown. It can then be compared throughout the remainder of the Makefile to separate any OS-sensitive variables and commands.
The key is that Windows uses semicolons to separate paths in the PATH variable whereas everyone else uses colons. (It's possible to make a Linux directory with a ';' in the name and add it to PATH, which would break this, but who would do such a thing?) This seems to be the least risky method to detect native Windows because it doesn't need a shell call. The Cygwin and MSYS PATH use colons so uname is called for them.
Note that the OS environment variable can be used to detect Windows, but not to distinguish between Cygwin and native Windows. Testing for the echoing of quotes works, but it requires a shell call.
Unfortunately, Cygwin adds some version information to the output of uname, so I added the 'patsubst' calls to change it to just 'Cygwin'. Also, uname for MSYS actually has three possible outputs starting with MSYS or MINGW, but I use also patsubst to transform all to just 'MSYS'.
If it's important to distinguish between native Windows systems with and without some uname.exe on the path, this line can be used instead of the simple assignment:
UNAME := $(shell uname 2>NUL || echo Windows)
Of course in all cases GNU make is required, or another make which supports the functions used.
Here's a simple solution that checks if you are in a Windows or posix-like (Linux/Unix/Cygwin/Mac) environment:
ifeq ($(shell echo "check_quotes"),"check_quotes")
WINDOWS := yes
else
WINDOWS := no
endif
It takes advantage of the fact that echo exists on both posix-like and Windows environments, and that in Windows the shell does not filter the quotes.
Note that Makefiles are extremely sensitive to spacing. Here's an example of a Makefile that runs an extra command on OS X and which works on OS X and Linux. Overall, though, autoconf/automake is the way to go for anything at all non-trivial.
UNAME := $(shell uname -s)
CPP = g++
CPPFLAGS = -pthread -ansi -Wall -Werror -pedantic -O0 -g3 -I /nexopia/include
LDFLAGS = -pthread -L/nexopia/lib -lboost_system
HEADERS = data_structures.h http_client.h load.h lock.h search.h server.h thread.h utility.h
OBJECTS = http_client.o load.o lock.o search.o server.o thread.o utility.o vor.o
all: vor
clean:
rm -f $(OBJECTS) vor
vor: $(OBJECTS)
$(CPP) $(LDFLAGS) -o vor $(OBJECTS)
ifeq ($(UNAME),Darwin)
# Set the Boost library location
install_name_tool -change libboost_system.dylib /nexopia/lib/libboost_system.dylib vor
endif
%.o: %.cpp $(HEADERS) Makefile
$(CPP) $(CPPFLAGS) -c $
Another way to do this is by using a "configure" script. If you are already using one with your makefile, you can use a combination of uname and sed to get things to work out. First, in your script, do:
UNAME=uname
Then, in order to put this in your Makefile, start out with Makefile.in which should have something like
UNAME=##UNAME##
in it.
Use the following sed command in your configure script after the UNAME=uname bit.
sed -e "s|##UNAME##|$UNAME|" < Makefile.in > Makefile
Now your makefile should have UNAME defined as desired. If/elif/else statements are all that's left!
I had a case where I had to detect the difference between two versions of Fedora, to tweak the command-line options for inkscape:
- in Fedora 31, the default inkscape is 1.0beta which uses --export-file
- in Fedora < 31, the default inkscape is 0.92 which uses --export-pdf
My Makefile contains the following
# set VERSION_ID from /etc/os-release
$(eval $(shell grep VERSION_ID /etc/os-release))
# select the inkscape export syntax
ifeq ($(VERSION_ID),31)
EXPORT = export-file
else
EXPORT = export-pdf
endif
# rule to convert inkscape SVG (drawing) to PDF
%.pdf : %.svg
inkscape --export-area-drawing $< --$(EXPORT)=$#
This works because /etc/os-release contains a line
VERSION_ID=<value>
so the shell command in the Makefile returns the string VERSION_ID=<value>, then the eval command acts on this to set the Makefile variable VERSION_ID.
This can obviously be tweaked for other OS's depending how the metadata is stored. Note that in Fedora there is not a default environment variable that gives the OS version, otherwise I would have used that!
An alternate way that I have not seen anyone talking about is using the built-in variable SHELL. The program used as the shell is taken from the variable SHELL. On MS-Windows systems, it is most likely to be an executable file with .exe extension (like sh.exe).
In that case, the following conditional test:
ifeq ($(suffix $(SHELL)),.exe)
# Windows system
else
# Non-Windows system
endif
Would have the same result as using the environment variable OS:
ifeq ($(OS),Windows_NT)
# Windows system
else
# Non-Windows system
endif
However, it seems the latter is the most popular solution, so I would recommend you stick with it.