[ILUG] introduction to programming

[Brian Foster]

  | From: philip at imageviewer.co.uk
  | Date: Wed, 25 May 2005 20:19:58 +0100
  | 
  | Does any one remember Coral? [ ... ]

 yes.  didn't use it, tho.

 anyone remember BLISS?  another systems programming language
 some DEC O/Ses were written in.  only language I know where
 there is an operator to make a reference an L-value (or was
 it an R-value, I don't recall now!  ;-(  ).

  | It takes compiled 'C' 65K to print "Hello World".  [ ... ]

 twaddle!
 the Unix 7th Edition kernel needed < 128KiB, and
 a typical “Hello world” still, today, needs < 200
 _bytes_.  not KiB, just bytes.  (evidence below.)

 the size bloat Philip is hinting at (which does
 exist — see below) is, AFAIK, mostly due to NLS.

=====(cut here and below)=====(results of test script below)=====
+ gcc -O2 h.c
Hello, world!
   text	   data	    bss	    dec	    hex	filename
    944	    256	      4	   1204	    4b4	./a.out
	linux-gate.so.1 =>  (0xffffe000)
	libc.so.6 => /lib/tls/libc.so.6 (0x4003b000)
	/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000)
+ gcc -O2 -static h.c
Hello, world!
   text	   data	    bss	    dec	    hex	filename
 373104	   3152	   4448	 380704	  5cf20	./a.out
	not a dynamic executable
+ diet gcc -O2 -nostdinc h.c
Hello, world!
   text	   data	    bss	    dec	    hex	filename
    159	      0	     12	    171	     ab	./a.out
	not a dynamic executable
+ diet gcc -O2 -nostdinc -static h.c
Hello, world!
   text	   data	    bss	    dec	    hex	filename
    159	      0	     12	    171	     ab	./a.out
	not a dynamic executable
+ /opt/i386-linux-uclibc/usr/bin/gcc -O2 h.c
Hello, world!
   text	   data	    bss	    dec	    hex	filename
    729	    200	      4	    933	    3a5	./a.out
	libc.so.0 => /opt/i386-linux-uclibc//lib/libc.so.0 (0x40007000)
	ld-uClibc.so.0 => /opt/i386-linux-uclibc//lib/ld-uClibc.so.0 (0x40000000)
+ /opt/i386-linux-uclibc/usr/bin/gcc -O2 -static h.c
Hello, world!
   text	   data	    bss	    dec	    hex	filename
    842	    108	     32	    982	    3d6	./a.out
	not a dynamic executable
=====(cut here and above)=====(results of test script below)=====

 dietlibc is the clear winner, requiring only 171
 bytes (decimal).

=====(cut here and below)=====(test size of hello world in C)=====
#!/bin/bash

rm -f h.c
cat >h.c <<\EOF
#include <unistd.h>

int
main(void) {
	static const char hi[] = "Hello, world!\n";

	return (write(1, hi, sizeof(hi)-1) != sizeof(hi)-1);
}
EOF

Try() {
	echo -E "+ $*"
	rm -f a.out
	"$@" && ./a.out && size ./a.out && ldd ./a.out
}

Try	gcc -O2		h.c
Try	gcc -O2 -static	h.c
Try	diet gcc -O2 -nostdinc		h.c
Try	diet gcc -O2 -nostdinc -static	h.c
Try	/opt/i386-linux-uclibc/usr/bin/gcc -O2		h.c
Try	/opt/i386-linux-uclibc/usr/bin/gcc -O2 -static	h.c
=====(cut here and above)=====(test size of hello world in C)=====

 offhand, I don't know how to not pick up
 the NLS stuff when using GNU glibc, but I
 _think_ it is possible?  (the main reason
 for thinking the bloat is mostly due to
 NLS is by looking at the symbol table.)

cheers!
	-blf-
-- 
Experienced (20+ yrs) kernel/software Eng: | Brian Foster   Montpellier,
 • Unix, embedded, &tc;  • Linux;  • doc;  | blf at utvinternet.ie   FRANCE
 • IDL, automated testing, process, &tc.   |  Stop E$$o (ExxonMobile)!
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