A query
hi I am new to c programming and had just started learning it . My friends recommended me to use gcc compilers . but i dont know where will i get this compiler and how to use this . my operating system is Windows XP SP2 . please let me know what should i do ? Thanking You Sincerely, Harsh
zero and pointer conversions in g++
I have this test code that I think g++ is selecting the wrong function when
the second argument is a zero. If compiled with HAVE_ASCII_DEFAULT 1 it
selects read(const char*, const char*) instead of read(const char*, const
Variant&), for test2a/test3a. If compiled with HAVE_ASCII_DEFAULT 0
compilation fails because test2a/test3a are ambiguous. Shouldn't all of the
tests select the Variant function, or am I missing something? Why do I have
to explicitly create a Variant when the argument is zero?
Tested w/ g++ 3.4.3 (Mandrakelinux 10.2 3.4.3-7mdk) and 4.0.1 (self compiled)
TIA,
Thomas
PS please CC as I'm not subscribed
#include
#include
#define HAVE_ASCII_DEFAULT 1
using std::string;
using std::ostream;
using std::cout;
using std::endl;
class Variant
{
public:
enum Type {
Invalid, Bool, Int, String
};
Variant() : i(), b(), s(), type(Invalid) { ; }
Variant(Type t) : i(), b(), s(), type(t) { ; }
Variant(bool b) : i(), b(b), s(), type(Bool) { ; }
Variant(int i) : i(i), b(), s(), type(Int) { ; }
Variant(const string& s) : i(), b(), s(s), type(String) { ; }
const char* type_name() const;
friend ostream& operator<<(ostream& os, const Variant& v);
private:
int i;
int b;
string s;
Type type;
};
const char* Variant::type_name() const
{
switch(type) {
case Bool: return "Bool";
case Int: return "Int";
case String: return "String";
default: break;
}
return "Invalid";
}
ostream& operator<<(ostream& os, const Variant& v)
{
os << "Variant(" << v.type_name();
switch(v.type) {
case Variant::Bool:
os << ", " << (v.b? "true": "false");
break;
case Variant::Int:
os << ", " << v.i;
break;
case Variant::String:
os << ", \"" << v.s.c_str() << '\"';
break;
default:
break;
}
return os << ')';
}
class Config
{
public:
Config() { ; }
string read(const char* pKey, const string& aDefault) const;
#if HAVE_ASCII_DEFAULT
string read(const char* pKey, const char* aDefault) const;
#endif
Variant read(const char* pKey, const Variant& aDefault) const;
};
#if HAVE_ASCII_DEFAULT
string Config::read( const char *pKey, const char *aDefault ) const
{
if (!aDefault)
return read(pKey, string());
return read(pKey, string(aDefault));
}
#endif
string Config::read( const char *pKey, const string& aDefault ) const
{
cout << __PRETTY_FUNCTION__ << '\t' << (pKey && *pKey? pKey: "null") << endl
<< "\taDefault = \"" << aDefault.c_str() << '"' << endl;
return aDefault;
}
Variant Config::read( const char *pKey, const Variant &aDefault ) const
{
cout << __PRETTY_FUNCTION__ << '\t' << (pKey && *pKey? pKey: "null") << endl
<< "\taDefault = " << aDefault << endl;
return aDefault;
}
int main(int, char**)
{
Config config;
// bool
config.read("test1", true);
config.read("test2a", false);
config.read("test2b", Variant(false));
config.read("test3a", bool());
config.read("test3b", Variant(bool()));
return 0;
}
Thumb optimization question
I have one question. So... have small sample programm.
[code]
int bar( int );
int foo( int a, int b )
{
return bar( a + b );
}
[/code]
If I compille it with out -thumb parameter, i have very clean code.
add r0, r1, r0
bx lr
But with -thumb parameter have unopimized code.
add r1, r1, r0
mov r0, r1
bx lr
All diff of it outrage on '*.27.combine' (key -da) optimization step. But I
long time can't understad how it work.
Can anybody help me with it?
--
Regards, Ivan
Re: A query
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Harsh Chandra wrote: > > I am new to c programming and had just started learning it . My > friends recommended me to use gcc compilers . but i dont know where > will i get this compiler and how to use this . my operating system is > Windows XP SP2 . please let me know what should i do ? Wrong list - this is a list for discussing development *of* GCC itself, not how to use it or where to obtain it. As for your question, see MinGW: http://www.mingw.org/ If you want a complete UNIX-like environment on Windows (along with GCC), see Cygwin: http://www.cygwin.com/ Thanks, Ranjit. - -- Ranjit Mathew Email: rmathew AT gmail DOT com Bangalore, INDIA.Web: http://ranjitmathew.hostingzero.com/ -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.2 (MingW32) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFDsNVIYb1hx2wRS48RAsH2AJ0VRIF/zwd+QA/NdxD7qQuKIxAS1ACfRcnw UlU0yKcCoj42gN6jOOTbi80= =PrmX -END PGP SIGNATURE-
Re: weakref miscompiling libgfortran
On 25/12/2005, at 8:51 PM, Richard Henderson wrote:
On Sun, Dec 25, 2005 at 07:36:16PM -0800, Geoff Keating wrote:
That targetm.binds_local_p is no longer reliable is a serious bug.
What's wrong with it? It should be answering 'false' for a
weakref...
It doesn't. Exchanging the TREE_PUBLIC check for the binds_local_p
check was the first thing I tried. At which point I realized that
we have Real Problems with this feature at the moment.
The code in default_binds_local_p_1 says:
/* Weakrefs may not bind locally, even though the weakref itself is
always static and therefore local. */
else if (lookup_attribute ("weakref", DECL_ATTRIBUTES (exp)))
local_p = false;
which comment, now that I reread it, is a little confused, but the
code looks fine, and it worked for me on Darwin. Perhaps you have a
local patch which is affecting this?
We've had Real Problems with this feature since it was introduced. I
expect it'll take at least another two or three months before it
settles down and starts to work on most targets; that's only to be
expected for such a far-reaching change to GCC's capabilities.
smime.p7s
Description: S/MIME cryptographic signature
