3 ms·

No, a ret instruction would probably segfault, depending on the content of the stack. To terminate a program you have to use the corresponding system call. On l

• lgeek 13y ago
  to3m is correct. On my GNU/Linux machine main() is called from __libc_start_main(). A ret instruction in main() returns to __libc_start_main(), which in turn calls exit().
• to3m 13y ago
  That (or something like it) is true for the process as a whole, but not necessarily for main. It's usual to call main from a library-provided function, so it returns just like any other function. This removes the need to special-case main in any way, and provides a space for any system-specific startup and shutdown code. If you've got VS2012, you can see this code in the file at something like "c:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\crt\src\crt0.c" (it should be easy to find for other versions - it's been in pretty much in that place, with that name, probably with those contents, since VC5 I think). For glibc, see http://sourceware.org/git/?p=glibc.git;a=blob;f=csu/libc-start.c;h=e5da3efd0699b37438841f3f048e5a84445de1ca;hb=HEAD#l300 http://sourceware.org/git/?p=glibc.git;a=blob;f=csu/libc-sta.... My post was a bit x86/VC++-specific but the principles have been common to all the C environments I've used. I don't think I've ever used one that by default called your startup function directly, bypassing C runtime initialisation. (Though it's very easy to set this up with Visual Studio.)