#40683 [NEW]: zend_operators.h generates discard qualifier compiler warning

[lstefani at fortresstech dot com]

From: lstefani at fortresstech dot com
Operating system: linux 2.6.12-1.1381_FC3smp
PHP version: 5.2.1
PHP Bug Type: Compile Warning
Bug description: zend_operators.h generates discard qualifier compiler warning

Description:
------------
Zend/zend_operators.h: In function `void* zend_memrchr(const void*, int,
unsigned int)':
Zend/zend_operators.h:250: warning: cast from `const void*' to `unsigned
char*' discards qualifiers from pointer target type
Zend/zend_operators.h:250: warning: cast from `const void*' to `unsigned
char*' discards qualifiers from pointer target type


In code snippet, line 250 refers to the two recasts of argument s.

Reproduce code:
---------------
static inline void *zend_memrchr(const void *s, int c, size_t n)
{
register unsigned char *e;

if (n <= 0) {
return NULL;
}

for (e = (unsigned char *)s + n - 1; e >= (unsigned char *)s; e--) {
if (*e == (unsigned char)c) {
return (void *)e;
}
}

return NULL;
}


Expected result:
----------------
No compiler warnings.


--
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[tony2001@php.net]

ID: 40683
Updated by: [email]tony2001@php.net[/email]
Reported By: lstefani at fortresstech dot com
-Status: Open
+Status: Feedback
Bug Type: Compile Warning
Operating System: linux 2.6.12-1.1381_FC3smp
PHP Version: 5.2.1
New Comment:

What compiler do you use?


Previous Comments:
------------------------------------------------------------------------

[2007-03-01 19:44:25] lstefani at fortresstech dot com

Description:
------------
Zend/zend_operators.h: In function `void* zend_memrchr(const void*,
int, unsigned int)':
Zend/zend_operators.h:250: warning: cast from `const void*' to
`unsigned char*' discards qualifiers from pointer target type
Zend/zend_operators.h:250: warning: cast from `const void*' to
`unsigned char*' discards qualifiers from pointer target type


In code snippet, line 250 refers to the two recasts of argument s.

Reproduce code:
---------------
static inline void *zend_memrchr(const void *s, int c, size_t n)
{
register unsigned char *e;

if (n <= 0) {
return NULL;
}

for (e = (unsigned char *)s + n - 1; e >= (unsigned char *)s; e--) {
if (*e == (unsigned char)c) {
return (void *)e;
}
}

return NULL;
}


Expected result:
----------------
No compiler warnings.



------------------------------------------------------------------------


--
Edit this bug report at [url]http://bugs.php.net/?id=40683&edit=1[/url]

[lstefani at fortresstech dot com]

ID: 40683
User updated by: lstefani at fortresstech dot com
Reported By: lstefani at fortresstech dot com
-Status: No Feedback
+Status: Open
Bug Type: Compile Warning
Operating System: linux 2.6.12-1.1381_FC3smp
PHP Version: 5.2.1
New Comment:

Sorry for the late response. Your email hit my company spam filter for
some reason. Just found it while going through the bulk mail folder.

To answer your question, I'm using the MIPS cross-compiler (GCC 3.3.2
and GLIBC 2.3.2) on Linux x86. I know that's not the latest GCC
compiler by a long shot, but just from reviewing the code, it does
appear that the const declaration is being discarded by recasting the
parameter as an unsigned char.


Previous Comments:
------------------------------------------------------------------------

[2007-03-09 01:00:01] php-bugs at lists dot php dot net

No feedback was provided for this bug for over a week, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".

------------------------------------------------------------------------

[2007-03-01 19:59:07] [email]tony2001@php.net[/email]

What compiler do you use?

------------------------------------------------------------------------

[2007-03-01 19:44:25] lstefani at fortresstech dot com

Description:
------------
Zend/zend_operators.h: In function `void* zend_memrchr(const void*,
int, unsigned int)':
Zend/zend_operators.h:250: warning: cast from `const void*' to
`unsigned char*' discards qualifiers from pointer target type
Zend/zend_operators.h:250: warning: cast from `const void*' to
`unsigned char*' discards qualifiers from pointer target type


In code snippet, line 250 refers to the two recasts of argument s.

Reproduce code:
---------------
static inline void *zend_memrchr(const void *s, int c, size_t n)
{
register unsigned char *e;

if (n <= 0) {
return NULL;
}

for (e = (unsigned char *)s + n - 1; e >= (unsigned char *)s; e--) {
if (*e == (unsigned char)c) {
return (void *)e;
}
}

return NULL;
}


Expected result:
----------------
No compiler warnings.



------------------------------------------------------------------------


--
Edit this bug report at [url]http://bugs.php.net/?id=40683&edit=1[/url]

[tony2001@php.net]

ID: 40683
Updated by: [email]tony2001@php.net[/email]
Reported By: lstefani at fortresstech dot com
-Status: Open
+Status: Wont fix
Bug Type: Compile Warning
Operating System: linux 2.6.12-1.1381_FC3smp
PHP Version: 5.2.1
New Comment:

You can safely ignore it.
And no, I can't reproduce this warning with GCC4 & GCC3.4.6 or any
other compiler.


Previous Comments:
------------------------------------------------------------------------

[2007-03-12 00:08:58] lstefani at fortresstech dot com

Sorry for the late response. Your email hit my company spam filter for
some reason. Just found it while going through the bulk mail folder.

To answer your question, I'm using the MIPS cross-compiler (GCC 3.3.2
and GLIBC 2.3.2) on Linux x86. I know that's not the latest GCC
compiler by a long shot, but just from reviewing the code, it does
appear that the const declaration is being discarded by recasting the
parameter as an unsigned char.

------------------------------------------------------------------------

[2007-03-09 01:00:01] php-bugs at lists dot php dot net

No feedback was provided for this bug for over a week, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".

------------------------------------------------------------------------

[2007-03-01 19:59:07] [email]tony2001@php.net[/email]

What compiler do you use?

------------------------------------------------------------------------

[2007-03-01 19:44:25] lstefani at fortresstech dot com

Description:
------------
Zend/zend_operators.h: In function `void* zend_memrchr(const void*,
int, unsigned int)':
Zend/zend_operators.h:250: warning: cast from `const void*' to
`unsigned char*' discards qualifiers from pointer target type
Zend/zend_operators.h:250: warning: cast from `const void*' to
`unsigned char*' discards qualifiers from pointer target type


In code snippet, line 250 refers to the two recasts of argument s.

Reproduce code:
---------------
static inline void *zend_memrchr(const void *s, int c, size_t n)
{
register unsigned char *e;

if (n <= 0) {
return NULL;
}

for (e = (unsigned char *)s + n - 1; e >= (unsigned char *)s; e--) {
if (*e == (unsigned char)c) {
return (void *)e;
}
}

return NULL;
}


Expected result:
----------------
No compiler warnings.



------------------------------------------------------------------------


--
Edit this bug report at [url]http://bugs.php.net/?id=40683&edit=1[/url]