Thread: Need a good guide g++ on how to compile code

I'm wokring on a project and there are a lot of different libraries that I need to link to (.a files). I am including these header files in my code, and I really have no idea how I'm supposed to do all of this.

Does anyone know of a good guide (with lots of examples) on how to do this?

Thanks!

Any ideas? I just need to know the different phases, etc.

For example, if I link to a .a file, to I need to include the header in with the -I flag? These things I don't know.

You never include headers with an -I flag; that's not what it's for. Have you read the manual? Do you know what "compiling" and "linking" and "libraries" mean, as words in this context?

Originally Posted by tabstop

You never include headers with an -I flag; that's not what it's for. Have you read the manual? Do you know what "compiling" and "linking" and "libraries" mean, as words in this context?

I'm not very familiar with those terms. I guess I can look at the manual, but I was hoping for more of a tutorial. I feel like what I'm doing is pretty basic. I have my own .h and .c files and am building a wrapper around an existing library, that's been compiled as a .a...

Have you tried typing the words g++ tutorial into a search engine?

Originally Posted by rags_to_riches

Have you tried typing the words g++ tutorial into a search engine?

yes, they just give pretty basic tutorials discussing -Wall and stuff. I need something a little more robust.

Originally Posted by Salem

There are only three relevant options you need worry about for additional libraries

-I for specifying where the pre-processor should look for .h files.
-L for specifying where the linker should look for .a files.
-l for specifying which .a files (the linker) should search in.

As for the names of .h files to #include in the source, and the names of the .a files to pass to the linker, well that's just down to reading the manual for each library you want to use.

ok, so when do I specify the -I, the -L, etc?

I just need a general tutorial that explains this stuff, the different phases, what they mean, etc. I find it hard that people just automatically know this stuff....

for a given file main.cpp, in a directory dir, if all the .h files are also in the directory "dir", do I need to specify those via -I? These things I have no idea. How do I specify the location of my .a file? things like that.

Ok, so if I'm linking to a .a file, when I do the -I phase, I don't need to specify .a's header files?

You really need to learn how to use a search engine, but I'll spoon feed you I guess: GCC tutorial - An Introduction to GCC

Originally Posted by rags_to_riches

You really need to learn how to use a search engine, but I'll spoon feed you I guess: GCC tutorial - An Introduction to GCC

I saw that. It's $20. I figured there'd be something else out there.

I've found some, actually, thanks.

'man gcc'
Or if you're not on a linux/unix system:
Directory Options - Using the GNU Compiler Collection (GCC)
Link Options - Using the GNU Compiler Collection (GCC)

Originally Posted by dayalsoap

for a given file main.cpp, in a directory dir, if all the .h files are also in the directory "dir", do I need to specify those via -I?

No, if all the header files are in the same dir as the source file you don't need -I if you use "file.h" for your #includes instead of <file.h>
Or if your header files are in 'dir/some_subdir' you can use
#include "some_subdir/file.h"
in your source file to avoid needing to use -I