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Re: hi,everyone. can anybody tell me where the C++ program start?

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On Fri, 20 Apr 2012 23:25:25 -0700, 伏虎 wrote:

> my question is I have a piece of asm code, and I want to start the C++
> main(), which function shall I call?

Note that a C++ program doesn't start by executing main(). It starts by
executing the constructors for variables defined at file scope. main() is
only called after that has been done.

> I am using gnu tool.  I compile the C++ code into .o files and  use ld
> to link them together. if i want to write a ld script to tell the ld to
> output a.out file or elf file, how to do that? i checked the asm code
> output by the gcc -S, and I cannot find the start or _start symbol.

When linking object files together with gcc or g++, it will also link the
appropriate "CRT" file (unless -nostartfiles is given), and possibly
libgcc as well.

You're better off asking this sort of question on a group dedicated either
to the toolchain (e.g. gcc and/or binutils) or the platform. For and
ELF-based Linux system, you might want to look at the source code for
ld-linux.so (which is part of glibc).

An ELF executable specifies the entry point in the e_entry field of the
header. If an ELF executable specifies a loader (on Linux, this is
normally ld-linux.so.2 or ld-linux-<arch>.so.2), execve() will call the
entry point of the loader; it's up to the loader to figure out how to run
the program.

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Thread

hi,everyone. can anybody tell me where the C++ program start? 伏虎 <fuhu314@hotmail.com> - 2012-04-20 20:43 -0700
  Re: hi,everyone. can anybody tell me where the C++ program start? ralph <nt_consulting64@yahoo.net> - 2012-04-21 00:52 -0500
    Re: hi,everyone. can anybody tell me where the C++ program start? 伏虎 <fuhu314@hotmail.com> - 2012-04-20 23:25 -0700
      Re: hi,everyone. can anybody tell me where the C++ program start? scott@slp53.sl.home (Scott Lurndal) - 2012-04-21 16:59 +0000
      Re: hi,everyone. can anybody tell me where the C++ program start? Nobody <nobody@nowhere.com> - 2012-04-22 03:34 +0100

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