quiet crest
From learncpp, I found out that static libraries have .lib extention and dynamic libraries have .dll extention. So if I have a folder which contains test.lib, test.h, main.cpp, and main.cpp includes the test.h header file. How do I use g++ to compile the program?
I normally do g++ main.cpp (without external libraries)
I don't use VS, I use sublime text and g++ from cmd
merry jewelBOT
quiet crest
add flag -static in the compile command
Can you write the full command please?
how do you do it?
ye?
mystic hinge
I wouldn't expect a library to have a main.cpp.
quiet crest
main.cpp is my main file
mystic hinge
Not illegal, ofc.
Just unexpected.
quiet crest
Wdym?
runic quiver
main.cpp is my main file
what is your directory structure, where are those files
quiet crest
you shall add -static (for static linking) and -ltest (to link the test.lib)
quiet crest
what is your directory structure, where are those files
Desktop/Testing
- main.cpp
- test.lib
- test.h
mystic hinge
Hang on.
Are you asking how to link with a static library?
quiet crest
you shall add -static (for static linking) and -ltest (to link the test.lib)
isn't .lib static library?
quiet crest
Hang on.
Are you asking how to link _with_ a static library?
yes
what's the full command I should use
runic quiver
#compilation phase
g++ -c main.cpp -I./ -o main.o
#linking phase
g++ main.o ./test.lib -o main
#run the program
./main
this should work
-I is an include directory - where #include-s are searched
quiet crest
isn't .lib static library?
bro, static linking and shared library are two different things
mystic hinge
-L is the directory
-l is the filename
Surely?
runic quiver
quiet crest
Umm...I use windows
so if I do g++ main.cpp, it will generate .exe and I don't think I can link it. Can I?
quiet crest
bro, static linking and shared library are two different things
can you explain more?
runic quiver
Umm...I use windows
so if I do `g++ main.cpp`, it will generate .exe and I don't...
well... here compilation will create the raw object file where the machine instructions of your .cpp file are stored and then immideately call the linker that will produce main.exe
quiet crest
static linking - you tell the linker to add all the code from libraries into your application
runic quiver
what I wrote are the two separete steps
the idea is that, when useing static linking, the size of your .exe grows
but when you use dynamic linking (not explained here yet) the machine instructions are left in an external .dll file
quiet crest
shared lib with extension .lib can be compiled with other programs.
flag -shared
Produce a shared object (in this case a library) which can then be linked with other objects to form an executable.
quiet crest
```
#compilation phase
g++ -c main.cpp -I./ -o main.o
#linking phase
g++ main.o...
Can you give an example for windows?
runic quiver
Can you give an example for windows?
you are using the g++ command in windows right?
quiet crest
yes
quiet crest
shared lib with extension .lib can be compiled with other programs.
flag -shared...
Arent shared libraries (.dll)s??
DLL is literally abbreviation of Dynamic Linked Library
"On Windows, dynamic libraries typically have a .dll (dynamic link library) extension, whereas on Linux, dynamic libraries typically have a .so (shared object) extension."
You load the functions from a DLL. No need ned to link your app to it.
mystic hinge
Desktop/Testing
- main.cpp
- test.lib
- test.h
Based on this I would hazard a guess and say it's probably
g++ main.cpp -l test -o myapp.exe
You don't need -I because all headers are local
You don't need -L because the lib is also local
quiet crest
Ye but here I am talking bout static libs
shared library can be compiled dynamically (the default) and also statically by adding the -static flag
quiet crest
Based on this I would hazard a guess and say it's probably
```bash
g++ main.cpp ...
so I can dobat g++ main.cppnormally?
mystic hinge
No, you need -l test to link with test.lib
mystic hinge
Yes
quiet crest
If I have many files, I can use cmd g++ main.cpp -l *.lib?
I mean if I have multiple .lib files
-l lib1 -l lib2 and so on
oukh
mystic hinge
Then repeat
g++ main.cpp -l test -l funky -l zigzag -o myapp.exe
you just need to pass the library name, no extension needed
ee a pain isn't it...but ty
you choose gcc LUL
mystic hinge
This is actually rather easy.
Venture into CMake, I dare you.
runic quiver
a fancy build system that calls the same command behind the scenes
mystic hinge
Oh dear,
I opened pandora's box.
Look into my neuralizer....
quiet crest
eee Ima use gcc for now
runic quiver
ee a pain isn't it...but ty
by the way, do you have some real library that you want to use?
quiet crest
Not now
quiet crest
I wanted to use cpr but idk how to install it
runic quiver
I wanted to use cpr but idk how to install it
what is cpr?
quiet crest
http client library
I am using my phone these days for C++ cuz I can't use my Windows PC. But I am unable to install custom libraries in it (phone)
quiet crest
what is cpr?
mystic hinge
Incidentally, someone may already have mentioned this, but the syntax to link with libraries is exactly the same whether is it a static lib or a dynamic lib.
quiet crest
ye probably monkey did it
-static
g++ main.cpp -static -l test -l funky -l zigzag -o myapp.exe
if you really need to link the library statically into your executable. This will make your executable slightly bigger
is -static flag necessary?
if you need the library statically linked. yes. if you already have the DLL, then no need. but the DLL must be in the same path, or in windows\system32
should I mention the other blackhole?
If I do not write the -static flag, will it generate exe + dlls?
mystic hinge
@Monkey, OP is linking with a library.
quiet crest
should I mention the other blackhole?
consider that I am a beginner
quiet crest
@Monkey, OP is linking **with** a library.
now I am more confused...
quiet crest
@Monkey, OP is linking **with** a library.
okay. I thought the DLL part in the first post is a requirement?
no no
I want to create a single executable
alright. got ya
quiet crest
-static
```
g++ main.cpp -static -l test -l funky -l zigzag -o myapp.exe
```
if ...
So this will work?
even with the static, yes
even with?
just change the library name to the ones taht you're linking
what if I don't include the static flag
runic quiver
I want to create a single executable
from the git repo of this library I am assuming that cmake is the way to go, which will cause you a real headache I assume
quiet crest
from the git repo of this library I am assuming that cmake is the way to go, whi...
._.
quiet crest
I need to learn about cmake
runic quiver
what URLs are you going to query?
quiet crest
Any?
I dont have any particular project in mind
I just want to learn C++ after python
runic quiver
I just want to learn C++ after python
so you have used the requests module in python already?
quiet crest
yes
runic quiver
and you haven't used C++ at all until now?
quiet crest
Absolutely
(not at all, I have done simple arithmatics programs)
quiet crest
what if I don't include the static flag
that one was referring to DLL condition earlier. it doesn't matter now does it?
oh nah I dont need dll
runic quiver
@mystic hinge
can you help with setting up cmake and running hello world with this library?
mystic hinge
It's a makefile generator.
quiet crest
oo
by the way I rather write my own make script 😅
Any idea how can I install c++ libraries with cmake?? (I don't have root perms so I can't add it to system folder)
runic quiver
Any idea how can I install c++ libraries with cmake?? (I don't have root perms s...
well, first, get on your windows PC please 😄
quiet crest
you need a text file called CMakeList.txt
:'(
ye
that text file have some cmake commands that cmake can understand to create a makefile
Ye but it tries to install it in the system directory
Can I make it portable instead?
cmake_minimum_required (VERSION 3.2)
set (CMAKE_C_STANDARD 11)
set (CMAKE_C_STANDARD_REQUIRED ON)
project(select VERSION 1.0)
add_executable(select select.c)
something like that that's mine for a class I teach
o
quiet crest
Can I make it portable instead?
.
quiet crest
Can I make it portable instead?
you need to link libgcc runtime statically hehe
quiet crest
you need to link libgcc runtime statically hehe
nvm :)
or add gcc directory to your system PATH environment
this app uses clang compiler
mystic hinge
You may need to set your CMAKE_CXX_COMPILER to point at clang.exe
quiet crest
i m on phone