Re: c_std/ and throw()

["Artem Khodush" <artem at duma dot gov dot ru>]

Jakub Jelinek <jakub@redhat.com> wrote:
> 
> ??
> Adding throw() (note the empty list) means the function cannot throw any
> exceptions, which means g++ can count on this.

Yep. You are right.

calling function marked with throw() (for gcc 2.96):

Sections:
Idx Name          Size      VMA       LMA       File off  Algn
  4 .text.f__Fv   0000002b  00000000  00000000  00000048  2**2
  5 .eh_frame    00000038  00000000  00000000  00000074  2**2

without throw:

use_bar.o:     file format elf32-i386

Sections:
Idx Name          Size      VMA       LMA       File off  Algn
  4 .text.b__Fv   0000004d  00000000  00000000  00000048  2**2
  5 .gcc_except_table 0000002c  00000000  00000000  00000098  2**2
  6 .eh_frame     00000040  00000000  00000000  000000c4  2**2

> And the vast majority of glibc functions cannot throw any exceptions, it is
> C code compiled with -fno-exceptions. The exceptions in glibc are functions
> like qsort or bsearch which take function pointer argument, which could be
> written in C++ and throw exceptions. These functions are compiled with
> -fexceptions and have no throw() at their prototypes in glibc headers.
> 

Yep. This is clear win to mark function as throw() if it is a leaf function
or calls only functions also marked as throw(). In other cases, the
situation is not so clear.

Best regards,
Artem.