soft and program: Digest for comp.lang.c++@googlegroups.com

Wednesday, February 25, 2015

Digest for comp.lang.c++@googlegroups.com - 25 updates in 3 topics

comp.lang.c++@googlegroups.com

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About software quality and programming - 1 Update
Getaddrinfo failing with: "servname not supported for ai_socktype" - 3 Updates
cmsg cancel <mcl6qb$96m$2@dont-email.me> - 21 Updates

JiiPee <no@notvalid.com>: Feb 25 09:05PM

On 25/02/2015 18:13, Jens Thoms Toerring wrote:
> wouldn't greet him with great friendliness but ask for him to
> be expelled before he ruins another evening.

> Regards, Jens

yes I agree, seems like you are right :).... even now he keeps sending
those messages, many of them in one day.

Getaddrinfo failing with: "servname not supported for ai_socktype"

woodbrian77@gmail.com: Feb 25 11:34AM -0800

> When I pass port to gettaddrinfo I get the error.
> The same code works fine on Fedora/GCC 4.9, so I'm thinking
> it has something to do with fgets or strtok in Clang.

I no longer think it has to do fgets or strtok. If I
change port from being a char* to

char port[6];

and then do this:

::strcpy(port,::strtok(nullptr,"\n "));

It works fine on PC-BSD/Clang. So I guess it
has to do with a C string that isn't null terminated.

Brian
Ebenezer Enterprises - "Like a bad tooth and an
unsteady foot is confidence in a faithless man
in time of trouble." Proverbs 25:19

http://webEbenezer.net

woodbrian77@gmail.com: Feb 25 11:45AM -0800

On Wednesday, February 25, 2015 at 1:22:38 PM UTC-6, Mr Flibble wrote:

> using a C compiler and write C++ code (i.e. use std::string and such)
> when using a C++ compiler.

> /Flibble

Hi, Leigh,

I use some of the older stuff and std:string when using
a C++ compiler.

Brian
Ebenezer Enterprises - "It is better to live in a
corner of the roof than in a house shared with a
contentious woman." Proverbs 25:24

http://webEbenezer.net

jt@toerring.de (Jens Thoms Toerring): Feb 25 09:01PM

> There's a comment in this thread

> http://stackoverflow.com/questions/10291923/getaddrinfo-failing-with-error-servname-not-supported-for-ai-socktype-in-c

> about getline not removing a newline character.

I dodmn't find anything about that in there. But getline()
isn't supposed to remove the newline characterr at the end,
see for example

http://pubs.opengroup.org/onlinepubs/9699919799/functions/getdelim.html

> I'm using fgets

You just said getline() and now it's fgets()? fgets() is a
different beast since it doesn't try to allocated memory
for the string but stops reading when the buffer is full
(but always makes sure there's a terminating '\0'). It
also doesn't remove the trailing linefeed (if one was
found and fit into the buffer).

> and strtok:

> port=::strtok(nullptr,"\n ");

In the first call of strtok() you must pass it the
address of the string it's to be working on. Only if
you want further snippets of what that string con-
tains you use a NULL pointer. If this is your very
first call of it then it probably will return a NULL
pointer (but since this case isn't documented it may
also crash the program or returns something else, no-
body can know who hasn't taken a closer look at how it
is implemented).

Note that the string you pass to strtok() must be
modifiable - strtok() changes it by replaces de-
limiters by '\0' in that string So you can't e.g.
use the result of applying the c_str() method on a
std::string! You'd have to make a copy in that case.

And if it's just for removing a trailing linefeed
it's probaly simpler to do just something like

if ( port[ strlen( port ) - 1 ] == '\n' )
port[ strlen( port ) - 1 ] = '\0';

What you get from getline() should never have more than
a single trailing '\n' (but it may have none if it read
the last line in a file and there wasn'tx one in that
last line).
Regards, Jens
--
\ Jens Thoms Toerring ___ jt@toerring.de
\__________________________ http://toerring.de

cmsg cancel <mcl6qb$96m$2@dont-email.me>

bleachbot <bleachbot@httrack.com>: Feb 25 08:46PM +0100

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soft and program

Wednesday, February 25, 2015

Digest for comp.lang.c++@googlegroups.com - 25 updates in 3 topics

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