Toolchain study digest

Some information I learned recently about GNU GCC toolchain and related topic from the book "Professional Linux Programming". Although I am familiar with most of the content, I'd just record here for a better memory.

* -fPIC (position independent code), used to generate code can be executed anywhere in the kernel, usually used to generate shared library.

* -shared -o libfoo.so, generate shared library directly, convenience provided by GCC.

* LD_LIBRARY_PATH, specify the additional path to shared library, other than regular /lib, /usr/lib ... directories.

GCC options:

* General Options:
-c (compilation only)
-S (generate assembly code)

* Language Options:
-ansi (ansi C90 standard)
-std=c89, gnu89, c99, gnu89 (use various ANSI C standards, or GNU C standards)
-fno-builtin (do not use the built-in version of printf/memcpy/etc in gcc, use external library version)

* Warning Levels:
-pedantic (strictly follow C standard, give warnings, or -pedantic-errors)
-Wformat (one of many warnings to check the code)
-Wall (a wide range of warnings)

* Debugging:
-g

* Optimization:
-O0, -O3
-Os

* Hardware options:
-march
-msoft-float
-mbig-endian, -mlittle-endian
-mabi

GNU Binutils

Assembler:

as -o foo.o foo.s

Linker:

ELF: Executable and Linking Format
crtbegin.o, crtend.o
Linking script: /usr/lib/ldscripts

Objcpy and objdump:
objdump -x -d -S hello_world

Kernel and toolchain:
* inline assembly
__asm__ __volatile__
* __attribute__, section, alignment, alias
* custom linker script, arch//kernel/vmlinux.lds

Useful Mutt documents and tips

I have started to use mutt as my main email client for a couple of months. It is powerful and convenient, especially for me as I am a lover of terminal programs.

I'd collect mutt relevant document here.

Training your mutt. http://www.linux.com/archive/articles/58760

Vim tricks

I've read another blog today about Efficient Editing with Vim. I learned some new tricks as the follows.

* g + h,j,k,l, to move screen line instead of real line. This can be real useful when you are editing an email with long lines.
* fx, Fx, go forward/backword to the next occurrence of x.
* (, ), move to the next sentence or the previous sentence
* xG, goto the xth line, the same as :x, just faster
* H, M, L, move to the top, middle, and end of the screen