Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Gaznevada]

Portability issue?

"case PHP_VAL_STRING: printf("string(%zd) \"%s\"\n", strlen(node->str_val), node->str_val); break;"

in src/webserver/src/php_core_lib.cpp

<stdio.h> and standard libc library

- in IRIX (for sure, tested)

and probably in

- AIX, see http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.basetechref/doc/basetrf1/printf.htm
- HP-UX, see http://docs.hp.com/en/B2355-90695/printf.3S.html
- Solaris, see http://docs.sun.com/app/docs/doc/816-0213/6m6ne387j?a=view

does not have a specific format descriptor for size_t
returned by strlen (a very quick look at the man page, not
a real test).

Given that the problem pops up in runtime and "the result
is unpredictable (K&R)" it is hard to figure out what really
happens without a core debug.

IMVHO I suggest to retain the old "%d" format descriptor
or check with configure the sanity of executable code with
a "%zd" as a format descriptor.

Cheers

--
Gaznevada

[lfroen]

Facts first: (quote from "man 3 printf")

       z      A  following integer conversion corresponds to a size_t or ssize_t argument. (Linux libc5 has Z with this meaning. Don't use
              it.)

CONFORMING TO
       The fprintf, printf, sprintf, vprintf, vfprintf, and vsprintf functions conform  to  ANSI  X3.159-1989  ("ANSI  C")  and  ISO/IEC
       9899:1999 ("ISO C99").  The snprintf and vsnprintf functions conform to ISO/IEC 9899:1999.

So, there's reason for "%z". Are you really poses AIX machine?

[Gaznevada]

Facts first: (quote from "man 3 printf")

       z      A  following integer conversion corresponds to a size_t or ssize_t argument. (Linux libc5 has Z with this meaning. Don't use
              it.)

CONFORMING TO
       The fprintf, printf, sprintf, vprintf, vfprintf, and vsprintf functions conform  to  ANSI  X3.159-1989  ("ANSI  C")  and  ISO/IEC
       9899:1999 ("ISO C99").  The snprintf and vsnprintf functions conform to ISO/IEC 9899:1999.

So, there's reason for "%z". Are you really poses AIX machine?

I understand that there is a reason for "%z". What I'm trying to say is:

1) Not all Unix flavors have "%zd"

2) IRIX does not have it, for sure.

3) Taking a quick look at man pages of printf for AIX, HP-UX and Solaris, there is
no mention of a specific format descriptor for size_t . Probably it means that
"%zd% is an unvalid format descriptor on such machines.

4) I have only a direct experience on IRIX.

5) Your "man 3 printf" is probably issued on a Linux machine. Isn't it? The point
is that I'm not talking about Linux.

Cheers

--
Gaznevada

[GonoszTopi]

Quote from "man 3 printf":

CONFORMING TO

       [...]

       glibc 2.1 adds length modifiers hh,j,t,z and conversion characters a,A.

So, %zd is not valid before glibc 2.1, and is valid only with glibc. This surely breaks builds that does not use the GNU C library (e.g. MSW, if it wasn't broken already; I don't know whether Macs use glibc or not). There already has been a request not to use glibc-specific features, or at least test for them correctly. Let's keep us to maximum portability.

[Gaznevada]

This surely breaks builds that does not use the GNU C library

Worse: build goes smoothly to an end but error pops up at runtime (SIGSEGV and
coredump) breaking amuleweb every now and then.

Cheers

--
Gaznevada

[lfroen]

Mac is OK with %z. Cygwin uses glib too, so I suppose it's safe bet that MSW is OK too? If so, I see no problem.

[Kry]

Why is printf even used for anything?

[GonoszTopi]

[...] I suppose it's safe bet that MSW is OK too?

MinGW uses msvcrt, and most likely MSVC too.

[lfroen]

Why is printf even used for anything?

For printing to stdout?

[lfroen]

The whole issue is of cause, silly. If %z present problem for MSVC - replace it with %d

[Kry]

Why is printf even used for anything?

For printing to stdout?

What happened to std::cout ?

[lfroen]

What happened to std::cout ?

No idea. Never used it (why bother? - something terrible happened to printf()?)

[Kry]

Yeah, that you refuse to remove a format spec that doesn't exist in some implementations

IMHO, printf should be avoided for C++ implementations and std::cout used.

 Anyway, my question stands, why is amuleweb printing anything like that to the console? That doesn't seem to be a informative message for the user.

[Gaznevada]

Just a remark: I'm not a developer, I'm a final user so
I'm primarily interested in a workin' code.

Now I put myself in John Smith's shoes: when I connect
to amuleweb from an external connection and after a while
the connection hangs up and I see a huge file named "core"
(assuming that I know what a "core" file is, I mean...)
my first thought is "aMule is broken, it does not work, let's
wipe it away".

Well, I think this is not a good service for aMule and it's
immaterial if developers choose to use printf or not:
I think that the only wrong choice is moving away from
portability.

My two cents.

Cheers

--
Gaznevada

[Kry]

We all know the application mustn't crash. We're talking solutions.