Re: [Tinycc-devel] compare quoted strings

[KHMan]

On 11/8/2010 8:44 PM, Christian Jullien wrote:
> In fact both gcc and tcc are correct because your snippet uses an undefined
> behavior.
>
> "a"=="a" compares the address of two strings which are the address of the
> first character, not the character itself as you said.
>
> Now, which one is correct? None or both.
>
> A litteral string is supposed to be constant as if declared:
>
> const char *s="a";
>
> Because litteral strings are constant, a compiler is allowed to share
> different strings and define only one instance.
> Gcc shares common strings and this "a"=="a" compares the addresses of the
> same object. It returns 1.

The OP can get the widely-available C standard draft #1256 and 
look at:

Annex J
J.1 Unspecified Behavior:
  ...
  - Whether two string literals result in distinct arrays (6.4.5).
  ...

Section 6.4.5 states the same thing. The section on initialization 
for literal strings also warns about a related kind of unspecified 
behaviour.

--
Cheers,
Kein-Hong Man (esq.)
Kuala Lumpur, Malaysia