I have written a makefile like this:
HEADER = -I./cygdrive/c/cpros/kajj/source4
LIBB = -L./cygdrive/c/cpros/kajj/source1 -L./cygdrive/c/cpros/kajj/source2
LIBRA = -larith -ldekk
target : game.o
gcc $(HEADER) $(LIBB) $< -o $# $(LIBRA)
game.o : game.c
gcc -c game.c
I have created my own static library and included the header file path and library path. When I execute my makefile it gives an error saying that
/usr/lib/gcc cannot find -larith -ldekk.
It is pointing to the lib/ directory but it is not over there: -ldekk and -larith are in source1 and source2 files respectively.
How to solve this error?
Instead of -L./cygdrive/c, use -L/cygdrive/c. The dot makes the library path relative from the current directory, i.e. it will look for a cygdrive subfolder of the current folder instead of drive C.
My revised Makefile libraries line is:
LIBS=-L/usr/lib/arm-linux-gnueabihf -lrtlsdr -lpthread -lm
This solved the issue in a Raspberry Pi 4 running the latest Raspbain as of Dec 30, 2019
Related
I have a situation where I am given a link to source directory which goes under the parent dir. The contents of the link cannot be modified. The link has a header and .c file. The header file includes a "Config.h" file. The Config.h can only reside in the parent dir because I cannot modify anything under the link. I have to use the sources in the link and compile the parent dir. Here is the directory structure.
ParentDir
|-TestSrc.c
|-TestSrc.h
|-Config.h
|-Makefile
|-LinkToSrcDir
|-Src.c
|-Src.h(#include "Config.h")
My makefile is very straightforward
CC = gcc
INC_DIR = -IParentDir -IParentDir/LinkToSrcDir
CFLAGS = -Wall -Wextra $(INC_DIR)
all: mybin
mybin: TestSrc.o Src.o
$(CC) $(CFLAGS) -o TestSrc.o Src.o
TestSrc.o: TestSrc.c
$(CC) $(CFLAGS) -c TestSrc.c
--- similar code for Src.o ----
Phony: clean (all the usual rm -f)
My problem is, since I cannot modify src.h, the make always complains that Config.h is not found(tried a few different ways). How do I write the Makefile to make src.h look for Config.h in parent dir?
The simplest way is to use a fully-qualified path for the compiler flags:
INC_DIR = -I$(CURDIR)/ParentDir -I$(CURDIR)/ParentDir/LinkToSrcDir
Just to be clear, when the compiler searches for header files using a relative path it always starts with the directory the source file appears in. It doesn't start with the working directory where the compiler is invoked.
From the GCC manual for example:
the preprocessor looks for header files included ... first relative to the directory of the current file
In your case, the current file is LinkToSrcDir/Src.h so all paths will be expanded relative to the directory LinkToSrcDir.
When you say a link above I assume you mean a symbolic link. In that case you may not be able to use something like -I.. because that will give you the parent of the directory linked to.
You pretty much have no alternative but to use a fully-qualified path in your -I options.
How to include headers located in project root compiling with GCC C++ compiler?
I want to tell GCC compiler to search for some header files in project root.
I do NOT want to make changes in code and use relative paths in #include directives - e.g. #include "../../myheader.h"
I compile source code I do not own and I do not want to maintain own version.
I do NOT want to specify absolute include path e.g. g++ -c -IC:\root_project_folder .. for obvious reasons.
I have tried: g++ -c -I .., g++ -c -I/ .. and g++ -c -I"/" .. but it does not work.
Please advise.
root_project_folder
|--myheader.h
|--src_folder
|-prog.cpp
The symbol for the current directory is ..
You're looking for -I.
I have a module file in the include directory, which I compile using Makefile from root directory.
$(FC) -c include/my_mod.F90
Compilation works fine, just my module shows up in the root directory instead of the include directory. How can I specify location of the output file?
I am using linux system, and I would like to support both gfortran and ifort.
Thank #albert and #francescalus, the solution is:
ifeq ($(FC),ifort)
FORTFLAGS=-module
else
FORTFLAGS=-J
endif
module:
$(FC) -c include/my_mod.F90 $(FORTFLAGS) include/ -o include/my_mod.o
When I call protoc like this
protoc --cpp_out=. path/to/test.proto
the files
path/to/test.pb.cc and
path/to/test.pb.h
are generated which is what I want. But, since the cc needs the h, the h is included like this
#include "path/to/test.pb.h"
which is not what I want. The background is that my build tool (scons) calls protoc from the project's root and not from the directory which includes the source files. I found no obvious option in the manpage or the help text.
So my next idea was to consider this as "correct" and adjust my build system, but: The two files are siblings in the directory tree, so when one includes the other, no path is needed. Even compiling by hand fails.
Can someone help me with that?
Doing find-replace on generated files is most likely easier
than reorganization of your build system (use sed command on Linux/unix).
What I ended up doing for my project is as follows:
Create a pb/ directory at the same level as your include/ and src/ directories.
Put your .proto files in there, and create a makefile. Write the following in it:
CXX = g++
CXXFLAGS = -O3
PROTOBF = $(shell find ./ -name '*.proto')
SOURCES = $(subst proto,pb.cc,$(PROTOBF))
OBJECTS = $(subst proto,pb.o,$(PROTOBF))
default: $(OBJECTS)
#echo -n
$(SOURCES): %.pb.cc : %.proto
protoc --cpp_out=. $<
$(OBJECTS): %.pb.o : %.pb.cc
$(CXX) $(CXXFLAGS) -c $< -o $#
Which will essentially generate and build the protobuffer files when invoked.
In your main makefile, simply add the following include path: -Ipb/.
And when including a protocol buffer header, use #include <whatever.pb.h>.
Add the object files generated in pb/ to your linking step. Myself I used:
PB_OBJS = $(shell find pb/ -name '*.pb.o')
And gave that to the linker along with the normal object files in obj/.
Then, you can probably call the pb/ makefile from the main makefile if you want to automate it. The important point is that protoc be called from the pb/ directory or the include will be messed up.
Sorry for the ugly makefiles. At least it works, and I hope this helps you...
I have a structure of code like this:
project_dir/
source1.c
subdir/
source2.c
The Makefile calls subdir/Makefile, so that the file subdir/source2.c is compiled in this way:
gcc -g -someoptions source2.c
and symbols in GDB link to source2.c instead of subdir/source2.c (with the result that GDB can not find symbols in source files). How should I write a Makefile or what options to use in gcc to get symbols using the relative path to the project main directory (or eventually the absolute path)?
I can not use:
cd .. && gcc -g -someoptions ../subdir/source2.c
because I would have to change references to header files in all files in subdir.
Your question is platform-specific (e.g. on Linux GDB should just work(TM), so I assume you are not on Linux).
One option is to build like this:
gcc -g ${PWD}/source2.c -o ...
Another option is to use GDB dir command to add ${TOP}/project_dir/subdir to the list of directories that GDB will search for sources.