GNU Make producing a totally different result - c++

This is confusing. I have my Makefile:
OBJECTS =
INCLUDE_BUILD_PATH = /Users/wen/Projects/include
# Change compilation settings here
COMPILE = g++
override COMPILE_FLAGS += -O2
# Change linker/compiler specific settings here
LD_FLAGS :=
CC_FLAGS := -c -I$(INCLUDE_BUILD_PATH)/bigint
# Add source extensions here
SRC_EXT = cpp cc
# Add header dependencies here
HEADERS = $(wildcard *.hpp) $(wildcard $(INCLUDE_BUILD_PATH)/*/*.hh)
# Add source files here
CC_FILES = $(wildcard *.cpp) $(wildcard $(INCLUDE_BUILD_PATH)/*/*.cc)
CC_O_BUFFER = $(CC_FILES)
CC_O_BUFFER := $(CC_O_BUFFER:.cpp=.o)
CC_O_BUFFER := $(CC_O_BUFFER:.cc=.o)
OBJECTS = $(CC_O_BUFFER)
# Change .exe name here
EXE_NAME = maketest
# Link object files
$(EXE_NAME): $(OBJECTS)
$(COMPILE) $(COMPILE_FLAGS) $(LD_FLAGS) -o $# $^
# Build source files
define compile_rule
%.o : %.$1
$$(COMPILE) $$(COMPILE_FLAGS) $$(CC_FLAGS) -o $$# $$<
endef
$(foreach EXT,$(SRC_EXT),$(eval $(call compile_rule,$(EXT))))
# Clean
clean:
rm -f $(OBJECTS) $(EXE_NAME)
# Debug Build
debug:
#echo "Rerun with COMPILE_FLAGS=-D_DEBUG"
# Print variables
print:
#echo $(CC_FILES)
#echo $(OBJECTS)
#echo $(HEADERS)
it compiled successfully at first, but then it stopped for no reason and this was the output:
Yoshi-Air:maketest wen$ make
c++ -c -o maketest.o maketest.cpp
maketest.cpp:4:10: fatal error: 'BigIntegerLibrary.hh' file not found
#include "BigIntegerLibrary.hh"
^
1 error generated.
the problem was, I didn't even tell it to use "c++" in the Makefile but "g++" instead. Also, when I cleared CC_FLAGS the -c was still there. It's like Make's having a mind of it's own.
If I use make print to print out my variables it seems to be all right:
maketest.cpp /Users/wen/Projects/include/bigint/BigInteger.cc /Users/wen/Projects/include/bigint/BigIntegerAlgorithms.cc /Users/wen/Projects/include/bigint/BigIntegerUtils.cc /Users/wen/Projects/include/bigint/BigUnsigned.cc /Users/wen/Projects/include/bigint/BigUnsignedInABase.cc
maketest.o /Users/wen/Projects/include/bigint/BigInteger.o /Users/wen/Projects/include/bigint/BigIntegerAlgorithms.o /Users/wen/Projects/include/bigint/BigIntegerUtils.o /Users/wen/Projects/include/bigint/BigUnsigned.o /Users/wen/Projects/include/bigint/BigUnsignedInABase.o
maketest.hpp /Users/wen/Projects/include/bigint/BigInteger.hh /Users/wen/Projects/include/bigint/BigIntegerAlgorithms.hh /Users/wen/Projects/include/bigint/BigIntegerLibrary.hh /Users/wen/Projects/include/bigint/BigIntegerUtils.hh /Users/wen/Projects/include/bigint/BigUnsigned.hh /Users/wen/Projects/include/bigint/BigUnsignedInABase.hh /Users/wen/Projects/include/bigint/NumberlikeArray.hh
Any help or advice will be appreciated. Thanks!
Update
I updated my print to print the expected execution of compile:
print:
#echo $(CC_FILES)
#echo $(OBJECTS)
#echo $(HEADERS)
#echo "Compiles with:"
#echo $(COMPILE) $(COMPILE_FLAGS) $(LD_FLAGS) $(CC_FLAGS)
Result:
maketest.cpp /Users/wen/Projects/include/bigint/BigInteger.cc /Users/wen/Projects/include/bigint/BigIntegerAlgorithms.cc /Users/wen/Projects/include/bigint/BigIntegerUtils.cc /Users/wen/Projects/include/bigint/BigUnsigned.cc /Users/wen/Projects/include/bigint/BigUnsignedInABase.cc
maketest.o /Users/wen/Projects/include/bigint/BigInteger.o /Users/wen/Projects/include/bigint/BigIntegerAlgorithms.o /Users/wen/Projects/include/bigint/BigIntegerUtils.o /Users/wen/Projects/include/bigint/BigUnsigned.o /Users/wen/Projects/include/bigint/BigUnsignedInABase.o
maketest.hpp /Users/wen/Projects/include/bigint/BigInteger.hh /Users/wen/Projects/include/bigint/BigIntegerAlgorithms.hh /Users/wen/Projects/include/bigint/BigIntegerLibrary.hh /Users/wen/Projects/include/bigint/BigIntegerUtils.hh /Users/wen/Projects/include/bigint/BigUnsigned.hh /Users/wen/Projects/include/bigint/BigUnsignedInABase.hh /Users/wen/Projects/include/bigint/NumberlikeArray.hh
Yoshi-Air:maketest wen$ make print
maketest.cpp /Users/wen/Projects/include/bigint/BigInteger.cc /Users/wen/Projects/include/bigint/BigIntegerAlgorithms.cc /Users/wen/Projects/include/bigint/BigIntegerUtils.cc /Users/wen/Projects/include/bigint/BigUnsigned.cc /Users/wen/Projects/include/bigint/BigUnsignedInABase.cc
maketest.o /Users/wen/Projects/include/bigint/BigInteger.o /Users/wen/Projects/include/bigint/BigIntegerAlgorithms.o /Users/wen/Projects/include/bigint/BigIntegerUtils.o /Users/wen/Projects/include/bigint/BigUnsigned.o /Users/wen/Projects/include/bigint/BigUnsignedInABase.o
maketest.hpp /Users/wen/Projects/include/bigint/BigInteger.hh /Users/wen/Projects/include/bigint/BigIntegerAlgorithms.hh /Users/wen/Projects/include/bigint/BigIntegerLibrary.hh /Users/wen/Projects/include/bigint/BigIntegerUtils.hh /Users/wen/Projects/include/bigint/BigUnsigned.hh /Users/wen/Projects/include/bigint/BigUnsignedInABase.hh /Users/wen/Projects/include/bigint/NumberlikeArray.hh
Compiles with:
g++ -O2 -c -I/Users/wen/Projects/include/bigint
That proves that make knows what I wanted, but when it builds it's completely different: c++ instead of g++?!
Update 2:
c++ invokes clang, installed on my system.
Solution by Alex B:
But from the compilation command line it looks like Make is trying to
use the implicit suffix rule, and ignores your pattern rule.
I tried .SUFFIXES: and yes, it reported a no-rule found. Thanks, I will go and consult the manual.

As I stated in the comment, it works in my environment (Mac OSX, GNU Make 3.81), so the issue may be that the makefile you've posted is incomplete or you are using a different version of Make.
But from the compilation command line it looks like Make is trying to use the implicit suffix rule, and ignores your pattern rule.
You can tell Make to ignore default rules by specifying an empty list of suffixes, so you can debug your issue further.
.SUFFIXES:

Related

variable not updating when executing bash code in makefile

I'm trying to write a makefile that contains some bash commands in order to collect the names of the cpp files from a folder.
SRC_FILES=""
CC = g++
CFLAGS = -g
gather-files:
for var in $$(cd ./src && (ls -all *.cpp | awk '{print $$9}')); \
do \
SRC_FILES+="./src/"+"$(var) "; \
done; \
game: gather-files
$(CC) -c $(CFLAGS) $(SRC_FILES)
The SRC_FILES and var variables seems not to update when I run the make game command.
What am I missing?
Ignore the relatively incomplete g++ command, I just want to know how to make the SRC_FILES variable contain all of the names of the cpp files in the src folder.
This is the output of make game:
g++ -c -g ""
clang: error: no input files
LATER EDIT:
Solution, as suggested:
SRC_FILES := $(wildcard src/*.cpp)
CC = g++
CFLAGS = -g
game: $(SRC_FILES)
$(CC) -c $(CFLAGS) $(SRC_FILES)
You are mixing shell commands with makefile commands. That's not valid. The entire recipe is sent to the shell to be run there. Once the recipe has been expanded (which happens once before the shell is invoked) the results cannot contain any make operations.
In short, it's not possible (technically it can be done but it's A Very Bad Idea (tm) so don't) to change make variables from within a shell recipe.
Why don't you use GNU make operations instead?
SRC_FILES := $(wildcard src/*.cpp)
game: $(SRC_FILES)
...
Of course, this is kind of a silly makefile because it will recompile ALL the source files if ANY source file changes. You could get equivalent behavior by just writing a script that ran the compiler.
Your 'Last Edit' is still not ideal, as it builds everthing every time. Try something like this:
SRC_FILES := $(wildcard src/*.cpp)
OBJ_FILES := $(SRC_FILES:.cpp=.o)
DEP_FILES := $(SRC_FILES:.cpp=.d)
#Important: this is =, not :=
DEP_FLAGS = -MT $# -MMD -MP -MF $(DEPDIR)/$*.d
game: $(OBJ_FILES)
$(CC) -o $# $(OBJ_FILES)
# Pattern rule to build .o files
$(OBJ_FILES): %.o : %.cpp %.d
$(CC) $(DEP_FLAGS) -c $(CFLAGS) $< -o $#
#dummy rule to prevent building .d files explicitly.
$(DEP_FILES):
include $(wildcard $(DEP_FILES))
As to what this does -- it first populates SRC_FILES with any cpp files it finds. It then generates a list of object and dependency files from that list. Then we do some magic dependency stuff, which is described here -- basically, when you compile a file, it generates a .d file with a list of all headers it depends on, so now, if anything changes, make knows to rebuild the .c file.
Then there's a static pattern rule to build all the .o files, and a rule to link them all together to the game. Last, but not least, it includes the DEP_FILES that happen to exist when you start make.

Using makefile arguments without foo=

I have a makefile I use to compile a single file. When I need to pass an argument, I use target=targetFile.
The script takes the argument, looks for the file (within the same directory) that has the same value as the argument and compiles it.
I use this for compiling problems from uhunt and uva, which use a single c++ file. So I dont' need multiple makefiles for multiple source files. Single makefile for multiple source files is the reason I made the makefile.
Here's the code I have so far
OBJS = $(target).o
CC = g++
CFLAGS = -Wall -g -std=c++11
INCLUDE = -I./$(target)
#default command to run
all : Main-$(target) clean run
#compile and build
Main-$(target) : $(OBJS)
$(CC) $(CFLAGS) $^ -o $#
%.o : %.cpp
$(CC) -c $(CFLAGS) $<
#remove object and any other garbage files.
clean:
rm -rf -d $(target).o *~ *% *# .#*
#remove the compiled file
clean-all:
$(clean) rm Main-$(target)
#run the compiled file
run:
./Main-$(target)
The command I use to compile is,
make target=sourceFile
Also I don't include the file extension, I have all my source file extensions to be cpp
What I want in the end is:
make sourceFile
Just a side note, for using the command clean and clean-all, I use
make target=sourceFile clean
make target=sourceFile clean-all
I'd prefer if I can use:
make sourceFile clean
make sourceFile clean-all
You may use common Makefile variable MAKECMDGOALS that contains all targets passed to make.
Please try this variant
CC = g++
CFLAGS = -Wall -g
MAKECMDGOALS := $(filter-out clean, $(MAKECMDGOALS))
.PHONY: $(MAKECMDGOALS)
$(MAKECMDGOALS):
$(CC) $(CFLAGS) $#.c -o Main-$#
clean:
rm -f *.o
Here the lines
$(MAKECMDGOALS):
$(CC) $(CFLAGS) $#.c -o Main-$#
will generate separate build targets for each word in MAKECMDGOALS.
Note, we need this Makefile to know that 'clean' is a target for removing stuff, but not to attempt build Main-clean. This why we remove clean from MAKECMDGOALS using filter-out function.
So if we run make a b clean, the build system will generate automatically targets for building Main-a and Main-b and then use already written clean target
Disclaimer -- this is a non-standard use of Make, and will therefore open up all kinds of corner cases, so I don't recommend it. This is better suited for a shell script calling make. That being said... it is an interesting question.
You can't do make xxx clean, and not have it try to build xxx (unless you do some really nasty cludge using recursive make, but I won't go there). You could do something like make clean-xxx though, as follows:
%:Main-%
Main-%:%.cpp
$(CC) $(CFLAGS) $< -o Main-$#
clean-%:
rm Main-$*
Notice that %-clean has a shorter stem, and therefor takes precedence over the % if the make target starts with clean-.

Makefile Pattern rule: Circular makefile.o <- makefile dependency dropped

I am working on a makefile for a C++ project that needs to support a few configurations, i.e. debug , release and maybe a few more customized ones in the future.
Currently, my naming convention for generated .o files is $(SOURCE_FULLPATH).$(CONFIGURATION).o. For instance, ABC.cpp generates ABC.cpp.debug.o in debug mode.
Now I would like to write the pattern rule for generating those object files in a configuration-independent way. What I did was: from each XX.o filename, I strip the .debug or .release suffix from XX, and use the remaining part of XX as the source filename.
%.o: $$(basename %)
$(CC) $(CC_FLAGS) $(INCLUDE_FOLDERS) -c -o $# $<
With this trick, I can build the executable correctly, except that I get one warning message from make:
make: Circular makefile.o <- makefile dependency dropped.
I am puzzled because I do not list makefile or makefile.o as a target or dependency anywhere in my makefile. I did a search on SO, but most questions about Circular dependency is on a specific user source file, rather than the makefile itself. Can anyone help me understand what causes the circular dependency, and how to get rid of this warning message?
A sample makefile that can reproduce this issue is listed below.
.SECONDEXPANSION:
PROJECT := helloworld
CC := clang++
BUILD_FOLDER := Build
OBJ_FILE_SUFFIX := .o
# Source
CPP_FILES :=\
Source/hello.cpp \
Source/mysqrt.cpp \
INCLUDE_FOLDERS := \
-IInclude
# MMD outputs the dependency files (".d" files). These files will be used by
# this makefile to allow for dependency checking on .h files.
CC_FLAGS += -MMD
EXISTING_OBJ_FILES = $(wildcard $(addsuffix *.o, $(basename $(CPP_FILES))))
##--------------------
## Targets definition
##--------------------
.PHONY:default
default: all
.PHONY:all
all: debug release
.PHONY:debug release
# Add a 'debug'/'release' suffix to the name of the object file
# e.g. hello.cpp -> hello.cpp.debug.o
debug release: OBJ_FILES=$(addsuffix .$#$(OBJ_FILE_SUFFIX), $(CPP_FILES))
debug release: $${OBJ_FILES} # Use Secondary Expansion to get the obj names
$(CC) $^ -o $(BUILD_FOLDER)/$(PROJECT)_$#
# Strip configuration name from the end of the object file name
%.o: $$(basename %)
$(CC) $(CC_FLAGS) $(INCLUDE_FOLDERS) -c -o $# $<
## clean: remove executable, all object files, and all dependency files
.PHONY:clean
clean:
-rm -f $(BUILD_FOLDER)/$(PROJECT) $(EXISTING_OBJ_FILES) $(EXISTING_OBJ_FILES:.o=.d)
# Include the dependent files so that in later builds, modified .h files
# will cause all .cpp dependent on them to rebuild
-include $(OBJ_FILES:.o=.d)
The folder structure is
makefile
Source
- hello.cpp
- mysqrt.cpp
Include
- mysqrt.h
The full output of make debug is
make: Circular makefile.o <- makefile dependency dropped.
clang++ -MMD -IInclude -c -o Source/hello.cpp.debug.o Source/hello.cpp
clang++ -MMD -IInclude -c -o Source/mysqrt.cpp.debug.o Source/mysqrt.cpp
clang++ Source/hello.cpp.debug.o Source/mysqrt.cpp.debug.o -o Build/helloworld_debug
Everything is good except for the first line.
I would also really appreciate it if anyone can point to me if there is any bad practice in my makefile (I am still a newbie in makefile). Thank you in advance!
GNU Make always attempts to update the makefile(s) it has read before
making anything else. If it finds rules and prerequisites that tell it
to update makefile(s), then it does so and then starts again from scratch -
including attempting to update the makefile(s). See 3.5 How Makefiles Are Remade.
In your recipe:
%.o: $$(basename %)
$(CC) $(CC_FLAGS) $(INCLUDE_FOLDERS) -c -o $# $<
you have provided make with a rule for making makefile.o from makefile.
It is also the inverse of the rule in the builtin recipe
%: %.o
$(LINK.o) $^ $(LOADLIBES) $(LDLIBS) -o $#
which makes an executable from a single object file. So your recipe has introduced the circularity:
makefile.o <- makefile <- makefile.o
when make is considering makefile itself as a target.
You could suppress the circularity by expressly deleting the builtin inverse rule,
by writing the empty rule:
%: %.o
in the makefile. Then you could observe the following confusion on the part of the
compiler:
$ make makefile.o
clang++ -c -o makefile.o makefile
clang: warning: makefile: 'linker' input unused
And the same would occur if you attempted to make any target that depended
on makefile.o.
It is probably safe to assume that you will have no targets that depend on
makefile.o. Nevertheless a rule that would attempt to
compile foo.o from any existing file foo is clearly more sweeping that you
want or need. For the particular pattern of dependency that you wish to capture:
foo.cpp.{debug|release}.o: foo.cpp
You'd be better off with:
%.o: $$(basename $$(basename %)).cpp
$(CC) $(CC_FLAGS) $(INCLUDE_FOLDERS) -c -o $# $<
Note, BTW, that in GNU Make conventions - the conventions that are
assumed by GNU Make's builtin rules - CC denotes your C compiler while
CXX denotes your C++ compiler. Likewise flags for the C compiler are
denoted CFLAGS and flags for the C++ compiler are denoted CXXFLAGS.
Flags for the preprocessor are denoted CPPFLAGS, and -Ipath options
- which are preprocessor options - are conventionally be passed through CPPFLAGS.

Unable to find headers with make

I have a (fairly simple) makefile adapted from here that I am attempting to use to build a project on Ubuntu. The project tree is fairly simple: Makefile is in the root project directory, and there are src/, include/, build/, and bin/, where source code, header files, object files, and executables are stored, respectively.
When I run make from the root directory of the project, I get the following error message:
Linking...
g++ src/Main.cpp src/Foo.cpp -o bin/runner
src/Main.cpp:1:19: fatal error: Foo.hpp: No such file or directory
#include "Foo.hpp"
^
compilation terminated.
src/Foo.cpp:1:19: fatal error: Foo.hpp: No such file or directory
#include "Foo.hpp"
^
compilation terminated.
make: *** [bin/runner] Error 1
All that's currently in the project is Main.cpp. which calls two test functions Foo() and Bar() from Foo.cpp, which references a header file Foo.hpp. Here is the makefile:
CC := g++ # This is the main compiler
SRCDIR := src # Directory for source code
BUILDDIR := build # Directory containing all object files, which are removed on "make clean"
TARGET := bin/runner # bin/runner contains the main executable for project
# bin/ contains all other executables in the project (such as tests)
SRCEXT := cpp # File extension of source code
# Look for all the source files in SRCDIR with the file extension specified above
SOURCES := $(shell find $(SRCDIR) -type f -name *.$(SRCEXT))
# Name all object files the same root name as the source files from which they came, but add a .o extension to the end
OBJECTS := $(patsubst $(SRCDIR)/%,$(BUILDDIR)/%,$(SOURCES:.$(SRCEXT)=.o))
# The -g flag specifies that debugging information should be produced in the native format of the OS
CFLAGS := -g -Wall
# Various flags for libraries that might need to be linked
INC := -I include # Ensures that all header files (in the include/ folder) are accessible for build
# Show the components that are currently being compiled/linked
# Also, this is the main procedure for make: The TARGET is built from the objects, and
# object files are built from source
$(TARGET): $(OBJECTS)
#echo " Linking..."
#echo " $(CC) $^ -o $(TARGET)"; $(CC) $^ -o $(TARGET)
$(BUILDDIR)/%.o: $(SRCDIR)/%.$(SRCEXT)
#mkdir -p $(BUILDDIR)
#echo " $(CC) $(CFLAGS) $(INC) -c -o $# $<"; $(CC) $(CFLAGS) $(INC) -c -o $# $<
# Directives for "make clean" which cleans all object files out of the build/ folder
clean:
#echo " Cleaning...";
#echo " $(RM) -r $(BUILDDIR) $(TARGET)"; $(RM) -r $(BUILDDIR) $(TARGET)
# Destroys everything in the build/ and bin/runner/ folders. Does not clean test executables.
.PHONY: clean
What am I missing here in order to get the header files to be properly linked?
EDIT: Here is the new makefile, and the current output:
# This is the main compiler
CC := g++
# Directory for source code
SRCDIR := src
# Directory containing all object files, which are removed on "make clean"
BUILDDIR := build
# bin/runner contains the main executable for project
# bin/ contains all other executables in the project (such as tests)
TARGET := bin/runner
# File extension of source code
SRCEXT := cpp
# Ensures that all header files (in the include/ folder) are accessible for build
INC := -I/include
# Look for all the source files in SRCDIR with the file extension specified above
# SOURCES := $(shell find $(SRCDIR) -type f -name *.$(SRCEXT))
SOURCES := $(wildcard $(SRCDIR)/*.$(SRCEXT))
# Name all object files the same root name as the source files from which they came, but add a .o extension to the end
# OBJECTS := $(patsubst $(SRCDIR)/%,$(BUILDDIR)/%,$(SOURCES:.$(SRCEXT)=.o))
OBJECTS := $(addprefix $(TARGET)/, $(notdir $(SOURCES:.cpp=.o)))
# The -g flag specifies that debugging information should be produced in the native format of the OS
CFLAGS := -g -Wall
# Various flags for libraries that might need to be linked
LIB := #-pthread -lmongoclient -L lib -lboost_thread-mt -lboost_filesystem-mt -lboost_system-mt
# Show the components that are currently being compiled/linked
# Also, this is the main procedure for make: The TARGET is built from the objects, and
# object files are built from source
$(TARGET): $(OBJECTS)
#echo " Linking..."
$(CC) $^ -o $(TARGET)
# #echo " $(CC) $^ -o $(TARGET) $(LIB)"; $(CC) $^ -o $(TARGET) $(LIB)
$(BUILDDIR)/%.o: $(SRCDIR)/%.$(SRCEXT)
#mkdir -p $(BUILDDIR)
$(CC) $(CFLAGS) $(INC) -c -o $# $<
# Directives for "make clean" which cleans all object files out of the build/ folder
clean:
#echo " Cleaning...";
#echo " $(RM) -r $(BUILDDIR) $(TARGET)"; $(RM) -r $(BUILDDIR) $(TARGET)
# Tests
# tester:
# $(CC) $(CFLAGS) test/tester.cpp $(INC) $(LIB) -o bin/tester
# Spikes
# ticket:
# $(CC) $(CFLAGS) spikes/ticket.cpp $(INC) $(LIB) -o bin/ticket
# Destroys everything in the build/ and bin/runner/ folders. Does not clean test executables.
.PHONY: clean
Output:
[scott]> make
make: *** No rule to make target `bin/runner/Foo.o', needed by `bin/runner'. Stop.
tl;dr
Don't put end-of-line comments on variable assignments in make. It doesn't work the way you might expect.
Explanation
Your makefile isn't running the steps you expect it is.
You shouldn't be seeing Linking... for the compilation step.
make shouldn't be attempting to create the target from the source .cpp files.
You should be seeing your INC and CFLAGS values on the compilation line (but you are getting linking output so obviously aren't seeing them).
That's why your header can't be found by the way, your linking line doesn't have -I on it anywhere.
The reason that's happening is because make is applying the wrong rule.
make is applying the wrong rule because your variables are being set incorrectly.
Your variables are being set incorrectly because your variables have values you don't expect.
The makefile you started from had errors the author wasn't aware of.
make is not always very smart.
When you write
FOO := some value # comment
you expect FOO to have the value some value but make sees things differently.
make gives it the value some value since it can't tell the difference between the space between some and value and the space after value and before the comment.
So when you run your shell command (with *.$(SRCEXT) unquoted) the shell just ignores the trailing spaces). (Try quoting *.'$(SRCEXT)' and see what you get.)
However when you then try to $(SOURCES:=.$(SRCEXT)=.o) make doesn't drop the spaces and you have actually written $(src/Main.cpp src/Foo.cpp:=cpp =.o) which, you may notice, is a pattern that doesn't actually match.
As a result $(OBJECTS) gets the unmodified value of $(SOURCES) and "confuses" the $(TARGET): $(OBJECTS) line later causing make to skip your compilation target.
(Oh, also, that's why your linking line has a million spaces between g++ and the first source file.)
Oh, also, you don't need to shell out for find there unless your src/ directory has sub-directories of its own (and even then not with some make magic) because $(wildcard $(SRCDIR)/*.$(SRCEXT)) will work just fine (and also would have failed earlier I believe given this problem).
Define an environment variable that has . (current working directory) first, then ./include (not just include subdirectory but as ,/include and rest of the INCLUDE dirs that you might already have because of the compiler or other software requirement)
set INCLUDE :=.:./include:$INCLUDE
Alternately, use:
INC := -I. -I./include
gcc -I option is as: -I dir
Adds the directory dir to the list of directories to be searched for header files. Directories named by '-I' are searched before the standard system include directories. If the directory dir is a standard system include directory, the option is ignored to ensure that the default search order for system directories and the special treatment of system headers are not defeated

Makefile that compiles all cpp files in a directory into separate executable

I am now studying C++. I want a makefile which will compile all of the cpp files in the current directory to separate executables. For example:
In a directory there are 3 c++ files, such as examp1.cpp, examp2.cpp and examp3.cpp. I want a makefile which will compile and link them and give examp1.exe, examp2.exe and examp3.exe
I have created a bash script to compile all of them and create exes but I think; that's not the exact way to do this.
I have a a Makefile for ".c", but that does not seem to work here. It is only creating object files and not actually linking it. It is as follows:
SRCS=$(wildcard *.c)
OBJS=(SRCS:.c=.o)
all: $(OBJS)
The above code compiles all the new and modified ".c" files to ".o" files with same name in the current directory.
The bash script I am using to create executables is as follows:
for i in ./*.cpp
do
g++ -Wno-deprecated $i -o `basename $i .cpp`".exe"
done
This means I want whatever ".cpp" files I put in that directory, by using a simple "make all" or anything like that it should compile.
A minimal Makefile that does what you want would be:
#Tell make to make one .out file for each .cpp file found in the current directory
all: $(patsubst %.cpp, %.out, $(wildcard *.cpp))
#Rule how to create arbitary .out files.
#First state what is needed for them e.g. additional headers, .cpp files in an include folder...
#Then the command to create the .out file, probably you want to add further options to the g++ call.
%.out: %.cpp Makefile
g++ $< -o $# -std=c++0x
You'll have to replace g++ by the compiler you're using and possibly adjust some platform specific setting, but the Makefile itself should work.
This is the Makefile that I use
CC = gcc
CFLAGS = -g -O2 -std=gnu99 -static -Wall -Wextra -Isrc -rdynamic -fomit-frame-pointer
all: $(patsubst %.c, %.out, $(wildcard *.c))
%.out: %.c Makefile
$(CC) $(CFLAGS) $< -o $# -lm
clean:
rm *.out
You should paste it somewhere in your home and whenever you change the dirctory just copy it there. I use an alias in my ~/.basrc to copy it
alias get_makefile_here='cp ~/Makefile ./'
Simply press make and bam, you're done. Also notice the fact that once you're done with the old files it will not rebuild their executable.
My answer builds on top of the answer by #Haatschii
I don't prefer to have the .out prefix to my binaries. Also I used his existing Make syntax to perform clean as well.
CXX=clang++
CXXFLAGS=-Wall -Werror -std=c++11
all: $(patsubst %.cpp, %.out, $(wildcard *.cpp))
%.out: %.cpp Makefile
$(CXX) $(CXXFLAGS) $< -o $(#:.out=)
clean: $(patsubst %.cpp, %.clean, $(wildcard *.cpp))
%.clean:
rm -f $(#:.clean=)
The simplest makefile you can create that might work for you is this:
all: examp1.exe examp2.exe examp3.exe
That will use make's default rules to create your three programs.