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Date: Sun, 16 Nov 2008 14:47:02 +0100
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Subject: RE: [PHP-DEV] Can someone explain me why this happens please?
From: thetaphi@php.net ("Uwe Schindler")

This is per definition: In C local variables are not initialized with =
anything! The weird characters you see are content from prior memory =
usage leftover from calls to other functions. Its just garbage. In C, =
local variables must always be initialized.

-----
Uwe Schindler
thetaphi@php.net - http://www.php.net
NSAPI SAPI developer
Bremen, Germany

> -----Original Message-----
> From: Chris Jiang [mailto:jiangcat@gmail.com]
> Sent: Sunday, November 16, 2008 2:36 PM
> To: internals@lists.php.net; "M. Karpel=C3=A8s"
> Cc: internals@lists.php.net
> Subject: Re: [PHP-DEV] Can someone explain me why this happens please?
>=20
> Ah, greet appreciation! The memset() way works perfectly, but the =
res[0]
> way didn't work.
>=20
> Beside, I think you are right. Although I'm just a beginner in C
> language, but from the experience of JS and PHP, also according to the
> document I've been searching all the time, there should be something
> related to time.h functions which might be more suitable for what I'm
> doing. However, at the mean time, I'm just trying to get 'strings' to
> work in C and Zend, hehe!
>=20
> Still, this is a really strange experience. Where are those characters
> come from? Shouldn't it be a clean array when I first created them?
> Anything related to the zval structure?
>=20
> Thank you again!
>=20
>=20
> M. Karpel=C3=A8s wrote:
> > Hi,
> >
> > Try initializing your "res" variable first.
> >
> > either:
> >
> > memset(&res, 0, sizeof(res));
> >
> > Or:
> >
> > res[0] =3D 0;
> >
> > Both will work, it all depends if you want to write "clean" code, of
> > "fast" code (and your definition of both).
> >
> > I believe there are cleaner way to do what you are doing, but I'll =
let
> > that to your curiosity.
> >
> >
> > Mark
> >
> > Le dimanche 16 novembre 2008 =C3=A0 21:15 +0800, Chris Jiang a =
=C3=A9crit :
> >> Hi all, since I started playing around with Zend API, I thought it
> would
> >> be better to start writing some small functions as practice. Then =
my
> >> entire weekend became nightmare.
> >>
> >> I've tried to add a function activated in dynamic module, and it =
gives
> a
> >> very strange result. This function is really simple: taking an =
integer
> >> as argument, returns a 'hhhh:mm:ss' format string. If additional
> >> argument (BOOL) is set to true, then the 'hhhh' will turn to 'DD =
hh'.
> >>
> >> Now, it works fine while compiled with GCC alone in standard C =
style,
> >> but while working as a PHP function, the result is like this:
> >>
> >> (!=E9=9D=A0=E5=A4=87h2339:44:05
> >> (!=E9=9D=A0=E5=A4=87=E7=AA=B5=E2=96=9297D 11:44:05
> >>
> >> What are the characters in front of them? Where did they come? It's
> >> really confusing......
> >>
> >> The original Zend style code is as follow:
> >>
> >> =
--------------------------------------------------------------------
> >>
> >> ZEND_FUNCTION(cj_format_clock)
> >> {
> >> 	char res[50], myb[10];
> >> 	long mys =3D 0;
> >> 	double myd, myh, mym;
> >> 	zend_bool useDay =3D 0;
> >>
> >> 	if ( zend_parse_parameters_ex(ZEND_PARSE_PARAMS_QUIET,
> ZEND_NUM_ARGS()
> >> TSRMLS_CC, "l|b", &mys, &useDay) =3D=3D FAILURE )
> >> 	{
> >> 		php_error(E_ERROR, "Expecting
> cj_format_clock([(INT)seconds])",
> >> get_active_function_name(TSRMLS_C));
> >> 		return;
> >> 	}
> >>
> >> 	if ( mys < 0 )
> >> 	{
> >> 		php_error(E_ERROR, "Number of second must be a possitive
> integer",
> >> get_active_function_name(TSRMLS_C));
> >> 		return;
> >> 	}
> >>
> >> 	if ( useDay )
> >> 	{
> >> 		myd =3D mys / 86400;
> >> 		mys %=3D 86400;
> >> 		sprintf(myb, "%.0f", myd);
> >> 		strcat(res, myb);
> >> 		strcat(res, "D ");
> >> 	}
> >>
> >> 	myh =3D mys / 3600;
> >> 	mys %=3D 3600;
> >> 	if ( myh < 10 )
> >> 		strcat(res, "0");
> >> 	sprintf(myb, "%.0f", myh);
> >> 	strcat(res, myb);
> >>
> >> 	strcat(res, ":");
> >>
> >> 	mym =3D mys / 60;
> >> 	mys %=3D 60;
> >> 	if ( mym < 10 )
> >> 		strcat(res, "0");
> >> 	sprintf(myb, "%.0f", mym);
> >> 	strcat(res, myb);
> >>
> >> 	strcat(res, ":");
> >>
> >> 	if ( mys < 10 )
> >> 		strcat(res, "0");
> >> 	sprintf(myb, "%d", mys);
> >> 	strcat(res, myb);
> >>
> >> 	RETURN_STRING(res, 1);
> >> }
> >>
> >
>=20
> > Hi,
> >
> > Try initializing your "res" variable first.
> >
> > either:
> >
> > memset(&res, 0, sizeof(res));
> >
> > Or:
> >
> > res[0] =3D 0;
> >
> > Both will work, it all depends if you want to write "clean" code, of
> > "fast" code (and your definition of both).
> >
> > I believe there are cleaner way to do what you are doing, but I'll =
let
> > that to your curiosity.
> >
> >
> > Mark
> >
> > Le dimanche 16 novembre 2008 =C3=A0 21:15 +0800, Chris Jiang a =
=C3=A9crit :
> >> Hi all, since I started playing around with Zend API, I thought it
> would
> >> be better to start writing some small functions as practice. Then =
my
> >> entire weekend became nightmare.
> >>
> >> I've tried to add a function activated in dynamic module, and it =
gives
> a
> >> very strange result. This function is really simple: taking an =
integer
> >> as argument, returns a 'hhhh:mm:ss' format string. If additional
> >> argument (BOOL) is set to true, then the 'hhhh' will turn to 'DD =
hh'.
> >>
> >> Now, it works fine while compiled with GCC alone in standard C =
style,
> >> but while working as a PHP function, the result is like this:
> >>
> >> (!=E9=9D=A0=E5=A4=87h2339:44:05
> >> (!=E9=9D=A0=E5=A4=87=E7=AA=B5=E2=96=9297D 11:44:05
> >>
> >> What are the characters in front of them? Where did they come? It's
> >> really confusing......
> >>
> >> The original Zend style code is as follow:
> >>
> >> =
--------------------------------------------------------------------
> >>
> >> ZEND_FUNCTION(cj_format_clock)
> >> {
> >> 	char res[50], myb[10];
> >> 	long mys =3D 0;
> >> 	double myd, myh, mym;
> >> 	zend_bool useDay =3D 0;
> >>
> >> 	if ( zend_parse_parameters_ex(ZEND_PARSE_PARAMS_QUIET,
> ZEND_NUM_ARGS()
> >> TSRMLS_CC, "l|b", &mys, &useDay) =3D=3D FAILURE )
> >> 	{
> >> 		php_error(E_ERROR, "Expecting
> cj_format_clock([(INT)seconds])",
> >> get_active_function_name(TSRMLS_C));
> >> 		return;
> >> 	}
> >>
> >> 	if ( mys < 0 )
> >> 	{
> >> 		php_error(E_ERROR, "Number of second must be a possitive
> integer",
> >> get_active_function_name(TSRMLS_C));
> >> 		return;
> >> 	}
> >>
> >> 	if ( useDay )
> >> 	{
> >> 		myd =3D mys / 86400;
> >> 		mys %=3D 86400;
> >> 		sprintf(myb, "%.0f", myd);
> >> 		strcat(res, myb);
> >> 		strcat(res, "D ");
> >> 	}
> >>
> >> 	myh =3D mys / 3600;
> >> 	mys %=3D 3600;
> >> 	if ( myh < 10 )
> >> 		strcat(res, "0");
> >> 	sprintf(myb, "%.0f", myh);
> >> 	strcat(res, myb);
> >>
> >> 	strcat(res, ":");
> >>
> >> 	mym =3D mys / 60;
> >> 	mys %=3D 60;
> >> 	if ( mym < 10 )
> >> 		strcat(res, "0");
> >> 	sprintf(myb, "%.0f", mym);
> >> 	strcat(res, myb);
> >>
> >> 	strcat(res, ":");
> >>
> >> 	if ( mys < 10 )
> >> 		strcat(res, "0");
> >> 	sprintf(myb, "%d", mys);
> >> 	strcat(res, myb);
> >>
> >> 	RETURN_STRING(res, 1);
> >> }
> >>
> >
>=20
> --
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