Can anybody prompt how to set optioins to g++ to include or use objects oriented system libraries?
I use: gcc-arm-none-eabi-10.3-2021.10 And use in make file the following PATH:
export PATH=$PATH:/home/io/test_system/gcc-arm-none-eabi-10.3-2021.10/bin/ And include pahs:
-I /home/io/test_system/firmware/lib_cm3/inc
-I /home/io/test_system/firmware/tests/Difficult_cpp_program/inc
But the linker cant recognize my object oriented cpp code(cpp&hpp) I do compilation via following string:
arm-none-eabi-g++ --specs=nano.specs -std=c++11 -O0 -Wall -g -mcpu=cortex-m3 -mthumb
Please help
Help in advaunce
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If I compile in two stages, using a particular language standard:
g++ -std=c++2a -c file1.cpp #compile source files
g++ -std=c++2a -c file2.cpp
g++ -std=c++2a file1.o file2.o -o program #link 'em
...can I leave the -std=c++2a out of the link command, or is it sometimes needed?
Version is gcc 10.
I guess you are compiling on Linux with a recent GCC. Be sure to read more about C++ and about your particular compiler (i.e. GCC 9 is not the same as GCC 10). Check with g++ --version what it is.
In practice you want to compile with warnings and debug information (in DWARF for GDB inside your ELF object files and executables), so use
g++ -std=c++2a -Wall -Wextra -g -c file1.cpp
and likewise for file2.cpp
Later (once your program is correct enough, e.g. has few bugs) you could want to ask the compiler to optimize it. So you could use
g++ -std=c++2a -Wall -Wextra -O3 -g -c file1.cpp
Practically speaking, you'll configure your build automation tool (e.g. GNU make or ninja) to run your compilation commands.
In rare cases, you could want to use link time optimizations. Then you need to both compile and link with g++ -std=c++2a -Wall -Wextra -O3 -g -flto and perhaps other options.
Be aware that link time optimization could almost double your build time.
You could also be interested by static analysis options of GCC 10 (or even by writing your own static analysis using GCC plugins).
From the research I have done, the problem seems to be with clang. If that is the case, how would I fix this on a Mac? Would switching to Ubuntu/Linux be a better option?
I'm not sure if it is relevant, but my professor is having us code using C syntax using g++ and saving our files as '.cpp' before we dive into C++.
Warning:
clang: warning: argument unused during compilation: '-ansi'
[-Wunused-command-line-argument]
Makefile:
CC = g++
calendar: main.o calendar.o appt.o day.o time.o
$(CC) main.o calendar.o appt.o day.o time.o -g -ansi -Wall -o calendar.out
%.o: %.cpp
$(CC) -Wall -c $<
You are correct in believing that this warning is issued by clang++ in these
circumstances and not by g++, and that you see it on your Mac because g++ is
really clang++.
The GCC option -ansi is meaningful for compilation and not meaningful
for linkage. Clang is warning you because you are passing it in your linkage recipe:
$(CC) main.o calendar.o appt.o day.o time.o -g -ansi -Wall -o calendar.out
where it is ineffective, and not passing it to your compilation recipe:
$(CC) -Wall -c $<
The wording of the diagnostic is misleading since it is provoked here
precisely by the absence of compilation. Nevertheless, it does
draw attention to a mistake on your part. Remove -ansi from your linkage recipe and add it to your compilation recipe.
I'm trying to link a really simple GLES2 & EGL program using g++ 4.9.1, on a Ubuntu Trusty system. I'm using the mesa libraries.
I'm getting linker errors for EGL functions:
test.cpp:(.text+0x342): undefined reference to `eglGetDisplay'
test.cpp:(.text+0x389): undefined reference to `eglInitialize'
test.cpp:(.text+0x40f): undefined reference to `eglCreateContext'
test.cpp:(.text+0x458): undefined reference to `eglCreatePbufferSurface'
test.cpp:(.text+0x49e): undefined reference to `eglMakeCurrent'
I am compiling test.cpp with
g++ -std=c++0x -Wall -Werror -lEGL -lGLESv2 -o test test.cpp
I've tried switching the order of libraries, which sometimes matters, but I get the same problem. Is there a library I'm missing here?
I've run readelf -Ws /usr/lib/x86_64-linux-gnu/mesa-egl/libEGL.so and all of the required functions are defined.
You should put libraries to the end of a command line
g++ -std=c++0x -Wall -Werror -o test test.cpp -lEGL -lGLESv2
I managed to fix this by compiling the C++ file to an object file, and then linking as a separate step. I'm not sure why this works, when the one-line compilation doesn't.
g++ -std=c++0x -Wall -Werror -c -o test.o test.cpp
g++ -o test test.o -lGLESv2 -lEGL
I've put the question to the community to try to figure out why: Single-command compile and link fails, separate steps work
I have a GNU build system with autoconf-2.69, automake-1.14.1, libtool-2.4.2. I've configured with --host=i686-linux on a x86_64 RHEL6 host OS to build a 32-bit program. The libtool command seems to be:
/bin/sh ../libtool --tag=CXX --mode=link g++ -I/home/STools/RLX/boost/include/boost-1_44 -m32 -g3 -Wall -static -o engine engine-main.o ../components/librlxvm.la /home/STools/RLX/boost/include/boost-1_44/../../lib/libboost_program_options-gcc42-mt-1_44.a -lz -lpthread -ldl -lrt -ldl -lz -lm
But the real command is to search the 64-bit libraries not the 32-bit libraries as shown below:
libtool: link: g++ -I/home/STools/RLX/boost/include/boost-1_44 -m32 -g3 -Wall -o engine engine-main.o -L/home/robert_bu/src/gcc/gcc-4.2.2/build-x86_64/x86_64-unknown-linux-gnu/libstdc++-v3/src -L/home/robert_bu/src/gcc/gcc-4.2.2/build-x86_64/x86_64-unknown-linux-gnu/libstdc++-v3/src/.libs -L/home/robert_bu/src/gcc/gcc-4.2.2/build-x86_64/./gcc ../components/.libs/librlxvm.a /home/STools/RLX/boost/include/boost-1_44/../../lib/libboost_program_options-gcc42-mt-1_44.a /home/STools/RLX/gcc-4.2.2-x86_64/lib/../lib64/libstdc++.so -L/lib/../lib64 -L/usr/lib/../lib64 -lc -lgcc_s -lrt -ldl -lz -lm -pthread -Wl,-rpath -Wl,/home/STools/RLX/gcc-4.2.2-x86_64/lib/../lib64 -Wl,-rpath -Wl,/home/STools/RLX/gcc-4.2.2-x86_64/lib/../lib64
The --host config seems to have no effect. Is there anyway to tell libtool that 32-bit libraries are what we want?
It seems that libtool uses "CC", "CXX" to check the library search path. After I set CC to "gcc -m32", and CXX to "g++ -m32", it works. So libtool does not add "-m32" automatically even if I try to build a 32-bit program on a 64-bit system.
You're being hit by the problem of libtool .la files expansion. In particular libstdc++.la is being expanded for you to a full path rather than a simple -lstdc++.
My suggestion is to remove .la file from the SDK you're using (/home/STools). This way libtool can't assume things for you. Usually the ones you have in the system are fine, because the libraries are already in the search path, so it does not need to use -rpath or the full path to the .so file.
Depending on how well the SDK was crafted, this might or might not work correctly, so take it with a grain of salt.
I have 3 apps written in Obj-C that I want to modify and convert to libraries, so I can use them in a Monotouch app.
Where do I find docs that tell me how to take Obj-C code and turn it into libraries?
Imagine you have a file called lib1.m
You will first have to compile it as object code. For instance:
gcc -Wall -framework Cocoa -o lib1.o lib1.m
That will create lib1.o
Then you'll have to decide wether you want a static or dynamic library.
To build a static library, you'll need a library object first:
glibtool --quiet --mode=compile gcc -o lib1.lo -c lib1.c
Then you can create the static library from the library archive:
glibtool --quiet --mode=link gcc -o lib1.la -c lib1.lo
To build a dynamic library:
libtool -dynamic -flat_namespace -lSystem -undefined suppress -macosx_version_min 10.6 -install_name /usr/local/lib/lib1.dylib -o lib1.dylib lib1.o
Note that for dynamic libraries, you must provide the install path when creating the library.