what is meaning of this instruction in details?

k84834 · 09-22-2012, 02:41 AM

in section 5.9, what is the meaning of below instruction in details ?
what is the value of CFLAGS variable?

Code:

cp -v gcc/Makefile.in{,.tmp}
sed 's/^T_CFLAGS =$/& -fomit-frame-pointer/' gcc/Makefile.in.tmp \
  > gcc/Makefile.in

druuna · 09-22-2012, 03:09 AM

Quote:

Originally Posted by k84834

in section 5.9, what is the meaning of below instruction in details ?

Code:

cp -v gcc/Makefile.in{,.tmp}
sed 's/^T_CFLAGS =$/& -fomit-frame-pointer/' gcc/Makefile.in.tmp \
  > gcc/Makefile.in

This:

Code:

cp -v gcc/Makefile.in{,.tmp}

makes a copy of Makefile.in named Makefile.in.tmp

This:

Code:

sed 's/^T_CFLAGS =$/& -fomit-frame-pointer/' gcc/Makefile.in.tmp > gcc/Makefile.in

Substitutes T_CFLAGS = to T_CFLAGS = -fomit-frame-pointer. End result will be written to gcc/Makefile.in.

Quote:

Originally Posted by k84834

what is the value of CFLAGS variable?

CFLAGS is not set here, T_CFLAGS is. CFLAGS is for the user to override (have a look at the content of gcc/Makefile.in file).

PS: There's no point in changing/playing with these flags when in chapter 5. Chapter 5 creates a sane temporary(!) environment which is used to build chapter 6. Once you reach chapter 6 you can experiment with these flags if you want/need to. Changing these flags in chapter 5 might even get you into trouble.

k84834 · 09-22-2012, 03:26 AM

so you say that I follow book's instruction to build temporary system, then if I want to build reduced system I use compiler options in chapter 6 after chrooting?

druuna · 09-22-2012, 03:46 AM

Quote:

Originally Posted by k84834

so you say that I follow book's instruction to build temporary system, then if I want to build reduced system I use compiler options in chapter 6 after chrooting?

What do you mean by reduced?

Using CFLAGS optimizes and might make the compiled program slightly smaller:
- http://linuxreviews.org/howtos/compiling/
- http://en.gentoo-wiki.com/wiki/CFLAGS

If by reduced you mean make smaller then you will probably be disappointed at the end result.

EDIT: Also have a look at this: http://lfs.130th.net/lfs/faq.html#optimizations

k84834 · 09-22-2012, 04:02 AM

what was the minimum size of LFS that you have built? how you built it ? please share your experiences.
Thank you

spiky0011 · 09-22-2012, 04:07 AM

How small did you want it? Also what end system did you want i.e gnome or just the basic lfs finished?

k84834 · 09-22-2012, 04:20 AM

for example I want to build a LFS for Thin client Or a GUI system as an end system.
do I first build a smallest LFS and then install needed package for intended system OR should build end system then do some work to reduce it ?
it is more comfortable to build an reduces LFS system then turn it to GUI , Multimedia , Server and so on, it isn't?
my first base LFS system Size is 398M and is so much big

druuna · 09-22-2012, 04:26 AM

Quote:

Originally Posted by k84834

what was the minimum size of LFS that you have built?

I really don't know. I have experimented with removing stuff, but that was years ago.

To be honest I don't see the point in reducing LFS's size. It is a minimal install already. The same is true for optimizing; The increase in speed is almost negligible and the amount of trouble you get yourself into during the build isn't worth it.

Quote:

Originally Posted by k84834

how you built it?

I removed files after I finished installing LFS (have a look here: http://www.linuxquestions.org/questi...s-book-870662/)

If you are going to build anything from BLFS on top of LFS I would follow the book and don't bother with optimizing/making smaller.

Quote:

Originally Posted by k84834

please share your experiences.

LFS is very minimal as-is, no need to reduce its size. You can remove the installed documents, man pages and debugging (http://www.linuxfromscratch.org/lfs/...pingagain.html). This will leave the base intact and makes it possible to start with BLFS without having any nasty surprises.

I also would think twice before removing the man pages/documents; You need those, especially when you aren't an experienced linux user (which I think you aren't...).

If BLFS isn't of any concern you can remove some of the LFS packages, but this will significantly reduce the LFS functionality.

Ask yourself this: Why do you want to do this in the first place?