Re: gcc4.1.2 and 4.3.2 has different default behavior

[Ian Lance Taylor <iant at google dot com>]

Yixuan Huang <yixuan178@gmail.com> writes:

> I have encountered one issue when write a simple test code.
> #inlcude <iostream>
> int main{
>   const char* str = "aaaa";
>   std::cout<<"str len: "<<strlen(str)<<std::endl;
>  return 0;
> }
>
> If I compile on gcc version 4.1.2 20070115 (SUSE Linux), it can be
> compiled successfully. Otherwise, on gcc version 4.3.2 [gcc-4_3-branch
> revision 141291] (SUSE Linux), it will show
> linux-lht2:/home/yixuan # g++ aa.cpp
> aa.cpp: In function âint main()â:
> aa.cpp:6: error: âstrlenâ was not declared in this scope
>
> I don't know where can I get the information to explain the different behavior?

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followups to gcc-help.  Thanks.

gcc 4.3 is more careful about having one C++ header file include
another.  The function strlen is defined in <string.h>.  In gcc 4.1
<iostream> #include'd <string.h>.  In gcc 4.3 it does not.

This is briefly mentioned at http://gcc.gnu.org/gcc-4.3/changes.html:
   "Header dependencies have been streamlined, reducing unnecessary
    includes and pre-processed bloat."

Ian