Re: ld: creating a dynamically linked executable ...

[kedar mhaswade <kedar dot mhaswade at gmail dot com>]

> > 2) ld -o use-of-lib use-of-lib.o -lc
> Many uses of -lc also require the use of the corresponding startup object
> files with names such as crt0.o, crt1.o, crtn.o, etc.  Use gcc for linking
> until you become an expert.
>   gcc -v -o use-of-lib use-of-lib.o

OK. Thank you for the tip (maybe man ld should indicate that --
"beware, this is a tool only for experts :-)"
.
However, I run into what seem like bigger issues:

$> gcc -o use-of-lib use-of-lib.o
use-of-lib.o: In function `_start':
(.text+0x0): multiple definition of `_start'
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 0 has invalid symbol index 11
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 1 has invalid symbol index 12
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 2 has invalid symbol index 2
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 3 has invalid symbol index 2
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 4 has invalid symbol index 11
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 5 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 6 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 7 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 8 has invalid symbol index 2
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 9 has invalid symbol index 2
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 10 has invalid symbol index 12
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 11 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 12 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 13 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 14 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 15 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 16 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 17 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 18 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 19 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 20 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 21 has invalid symbol index 13
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_info):
relocation 22 has invalid symbol index 21
/usr/bin/ld: /usr/lib/debug/usr/lib/i386-linux-gnu/crt1.o(.debug_line):
relocation 0 has invalid symbol index 2
/usr/lib/gcc/i686-linux-gnu/4.6/../../../i386-linux-gnu/crt1.o:/build/buildd/eglibc-2.15/csu/../sysdeps/i386/elf/start.S:119:
first defined here
/usr/lib/gcc/i686-linux-gnu/4.6/../../../i386-linux-gnu/crt1.o: In
function `_start':
(.text+0x18): undefined reference to `main'
collect2: ld returned 1 exit status

I don't understand what's going on. Is my assembly source code incorrect?

>
> > $> ./use-of-lib
> > zsh: no such file or directory: ./use-of-lib
> zsh has a bug in its error reporting.  It is not ./use-of-lib which cannot
> be found, but rather the [PT_]INTERP which cannot be found.
> To be fair to zsh, the kernel does not say which file suffers ENOENT.
> However, *all* shells could be more user-friendly in this case.
> Obviously ./use-of-lib does exist (and most shells check for existence and
> +x permission _before_ trying execve()), so the shell should investigate
> further instead of emitting a message that makes no sense.



$ readelf --segments /bin/date
  INTERP         0x0000000000000238 0x0000000000400238 0x0000000000400238
                 0x000000000000001c 0x000000000000001c  R      1
      [Requesting program interpreter: /lib64/ld-linux-x86-64.so.2]

So /lib64/ld-linux-x86-64.so.2 also must exist in order for /bin/date to run.