| 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 <2017> 2018 2019 2020 2021 2022 2023 2024 | Index | 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 <2017> 2018 2019 2020 2021 2022 2023 2024 |
| <== Date ==> | <== Thread ==> |
|---|
| Subject: | Re: motor module compile problems |
| From: | "Lang, Keenan C." <[email protected]> |
| To: | "Johnson, Andrew N." <[email protected]>, "Rivers, Mark L." <[email protected]>, 'Jörn Dreyer' <[email protected]>, "[email protected]" <[email protected]> |
| Date: | Wed, 8 Nov 2017 17:04:47 +0000 |
|
For what it's worth, Bjarne Stroustrup doesn't discourage the use of NULL, calling the use of "0" instead to be an aesthetic difference.
It was discouraged in pre-standard code, but many of the reasons why it was discouraged largely still apply to the use of "0" and "\0". The current recommendation is to use C++11's nullptr keyword. From: [email protected] <[email protected]> on behalf of Andrew Johnson <[email protected]>
Sent: Wednesday, November 8, 2017 10:27:16 AM To: Rivers, Mark L.; 'Jörn Dreyer'; [email protected] Subject: Re: motor module compile problems On 11/08/2017 08:33 AM, Mark Rivers wrote:
> All of this code is C++. In general it is recommended not to use NULL at > all in C++, use 0 instead. So I would suggest changing "(char) NULL" to "0". To clarify and amplify what Mark wrote, the character with value zero used to be named NUL (single L) in the old ASCII charts that I remember, and I have also seen it called Nil. Apparently some people re-use the macro NULL for this as in the code that Jörn showed, but to me doing so is very confusing. I generally use 0 (no quotes) as Mark suggests, while others use '\0' which explicitly tells the compiler that this is a char. - Andrew > -----Original Message----- > From: [email protected] [mailto:[email protected]] On Behalf Of Jörn Dreyer > Sent: Wednesday, November 08, 2017 8:13 AM > To: [email protected] > Subject: motor module compile problems > > Hi, > > I have had some trouble compiling the motor module (from git) on a openSuSE > Tumbleweed system with gcc 7.2.1. It fails in all motor drivers at the calls > of send_message where the last parameter is passed as (char) NULL. But in the > definition of send_message the last parameter is defined as char*. > What would be the correct fix for this? One could > 1. modify all calls to send_message(..,..,(char) NULL) to > send_message(..,..,(char*) NULL), or > 2. modify the definition of send_message(..,..,char*)to > send_message(..,..,char), but then other calls may fail. > > I chose the first solution to get it compiled. If needed I can send a patch > file to correct all necessary lines. > > Regards, > > Jörn > > -- Arguing for surveillance because you have nothing to hide is no different than making the claim, "I don't care about freedom of speech because I have nothing to say." -- Edward Snowdon | ||