I am writing a bluetooth driver for debian based linux. I have used module_param to send command line argument to a module. It takes 3 arguments. First is the variable to store the argument value, second is the type of the argument and third is the permission.
my code looks like this....
#include <linux/module.h>
bool x =1;
module_param(x,bool,0000);
one more thing is I am compiling the module using g++ and I know people write module in C.
the error I am getting is like this.
test.cc:10:error: types may not be defined in 'sizeof' expressions
Please post if you have an answer for it.
There was some problem with verfiy.h file with c++. They have fixed it in latest g++ compiler (g++ 3.2.2 and 4.0.1), try downloading the latest g++ and compile. Please go through this link http://www.mail-archive.com/bug-gnulib#gnu.org/msg01306.html. Hope this answers your question :-).
Related
I'm trying to move a code from linux to windows to use it in Visual Studios. The first problem I came across was was that unistd.h didn't exist. Should have seen that coming. So try to see if there's a windows equivalent and I stumble across this:
Is there a replacement for unistd.h for Windows (Visual C)?
Following this example, I create put the code in a unistd.h file for the code, but notice it depends on getopt.h, so I follow another link to the github page and put that code in a getopt.h file. When I try to run the code, I get an error "a value of type "const char*" cannot be used to initalize an entity of type 'char*'", for getopt.h. Why is this happening? How would I go about dealing with the issue? Thanks!
So in my CSE course we are given a header file to use right now for our programs that we're writing.
Unfortunately I can't get terminal to compile using that header, it gives quite a few errors (compiling with just 'g++'). Also, when I'm at my university and I'm using PuTTY I get the same errors while using this header. However, I don't get the errors when I compile with 'g++ -std=c++14'.
I've tried compiling with this command on terminal on my mac, but it says it doesn't recognize the c++14 part.
dhcp-10-202-147-243:hw1pr1 Admin$ g++ -std=c++14 hw1pr1.cpp
error: invalid value 'c++14' in '-std=c++14'
Any help on how I could get this to work would be greatly appreciated. Hopefully this all made some sort of sense.
Here's the error I get when I compile with the header file I'm talking about in terminal with just g++.
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/ext/hash_map:212:5: warning:
Use of the header <ext/hash_map> is deprecated. Migrate to <unordered_map>
[-W#warnings]
# warning Use of the header <ext/hash_map> is deprecated. Migrate to ...
^
In file included from read_first_name.cpp:1:
./std_lib_facilities_4.h:43:20: error: no matching function for call to object
of type 'hash<char *>'
return hash<char*>()(s.c_str());
^~~~~~~~~~~~~
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/ext/__hash:39:12: note:
candidate function not viable: 1st argument ('const value_type *'
(aka 'const char *')) would lose const qualifier
size_t operator()(char *__c) const _NOEXCEPT
^
In file included from read_first_name.cpp:1:
./std_lib_facilities_4.h:112:8: warning: comparison of unsigned expression < 0
is always false [-Wtautological-compare]
if (i<0||size()<=i) throw Range_error(i);
~^~
./std_lib_facilities_4.h:118:8: warning: comparison of unsigned expression < 0
is always false [-Wtautological-compare]
if (i<0||size()<=i) throw Range_error(i);
~^~
3 warnings and 1 error generated.
This error doesn't happen and the program will compile fully when I use PuTTY and 'g++ std=c++14'
There's lots of change between C++ standards, so what is valid in one revision need not be in another.
g++ defaults to -std=gnu++98 for C++, which is the decades old C++98-standard enhanced with GNU extensions (most of which are conformant).
Choose the proper revision: -std=c++1y -pedantic is a very close approximation to C++14.
What changes introduced in C++14 can potentially break a program written in C++11?
Looking at what you say you're having to use and the name format of that .cpp file, I think I'm in the same class. A year later, looks like, but here's my solution for archive's sake:
The std_lib_facilities.h header comes with the Bjarne Stroustrup textbook, "Programming: Principles and Practices Using C++". For those unaware, Bjarne Stroustrup invented C++ (he has a pretty good idea what he's talking about). Incidentally, the book is a fantastic way to learn C++, if one takes the time to actually read it. The std_lib_facilities.h header is just a convenient header file for beginners in C++, containing links to all the major standard libraries used in the textbook, as well as some helper functions that help account for potential mistakes or errors, or are just convenient for learning (such as an error() function that handles simple exception throwing for the student, or adding an "out of bounds" check for vectors). It's ultimately just a way to allow students to hop right into code without having to learn specifics about the header.
Stroustrup keeps updated with C++ and thus includes several libraries that require the c++11 standard. The CSCE department wants its students (at least in this early class) to connect to the department's Unix system and compile from there, in order to avoid confusion with downloading and updating compilers.
I happened to already have had a couple C++ classes beforehand, and thus already had g++ set up on my Ubuntu laptop. I avoided including the std_lib_facilities for as long as possible since I was getting the same error as Topic Creator Joe, where g++ didn't recognize the "c++11" part (manually including the required libraries worked fine until we had to use a class from the textbook that used one of the header's helper functions) . Eventually, I found a help topic online that advised me simply to update my g++ compiler to 4.7 or higher, since 4.6 and lower doesn't have support for C++11 (or, of course, C++14). It was oddly rather involved compared to updates one might be used to on Mac or Windows, and I doubt the exact process would apply, but that is (was?) likely the problem: it's just an older version of g++, and it needs an update to compile C++11 and later. I recommend searching for ways to update g++/gcc for Mac.
Should, y'know, anyone else with this problem stumble upon this and not have their problem solved yet.
It's a simple question really, and refers to Linux (as opposed to Windows or Mac).
How do you generate a warning message from the C or C++ compiler that must have the word 'suspicious' in it, and must refer to (-Wmain).
(update)
Thanks Boann - I got some of those Warnings, but I also got Error - error: ‘::main’ must return ‘int’.
The reason I'm asking this question is that a week ago my compiler (GCC 4.8.1) came out with this warning saying 'suspicious' and that it was caused by Wmain. So I put -Wno-main and the warning went away and it compiled fine. Just recently it has started complaining making it an actual Error and not compiling. So I'm kind of worried that somehow the mother ship has covertly updated my compiler over the internet, without me knowing, and changed it to treat it as error. (I was probably using 'int4' as the return type which I forever have typedef'd as signed long int.
I note there's -Wmain referenced in g++ man page so it must be for something, but what warning is there that isn't overruled by an error??
At offset 557284 (decimal) of the g++ executable I found "Warn about suspicious declarations of "main".
For what it's worth,
struct suspicious {};
int main(suspicious) {}
Output with g++ -Wall, GCC 4.8.2:
warning: first argument of 'int main(suspicious)' should be 'int' [-Wmain]
If you refer to the -Wmain parameter of GCC, you get the warning by giving main odd arguments, an odd return type, or giving it static linkage. This will do it:
static float main(float x) {
return 0;
}
Compiled with gcc -Wmain, it displays these warnings; they do not actually contain the word 'suspicious' though:
warning: return type of 'main' is not 'int'
warning: first argument of 'main' should be 'int'
warning: 'main' takes only zero or two arguments
warning: 'main' is normally a non-static function
I just downloaded the sources for gcc 4.8.1 and searched all relevant files for the word "suspicious".
There are a number of occurrences, but as far as I can tell, there's no way an error message for a C or C++ source file can contain the word "suspicious". It's possible but unlikely that there was a local modification.
Is it possible that you're mistaken about what the error message said? If you have a log containing the error message, please update your question to show the exact message your received.
If you're concerned that your compiler may have been updated without your knowledge, you might check the timestamp of the compiler executable and of any programs it invokes (use gcc -v to check that). But gcc itself doesn't automatically update itself. If you're using it on a system administered by someone else, automatic updates are to be expected. If you administer the system yourself, you may have configured it to update software without manual intervention; if so, that's not a gcc issue. I don't know what "mother ship" you're referring to.
I was wondering if someone could help me with this.
I've retrieved the source code for the gnuplot-iostream interface from http://www.stahlke.org/dan/gnuplot-iostream/. However, when I attempt to compile the code using the command:
]$ cmake .; make
I get the following compiler error
/.../gnuplot-iostream.h: In constructor ‘Gnuplot::Gnuplot(const std::string&)’:
/.../gnuplot-iostream.h:427: error: ‘never_close_handle’ is not a member of ‘boost::iostreams’
I'm using Scientific Linux 6.2 (kernal 2.6.32-220.23.1.el6.x86_64), g++ 4.4.6, and have boost libraries installed (/usr/include/boost/iostreams/ exists).
Any assistance would be very much appreciated.
D
enum file_descriptor_flags was added in boost::iostreams only in 1.44.0.
enum file_descriptor_flags
{
never_close_handle = 0,
close_handle = 3
};
So, the solution is simply update the boost library (thanks ForEveR).
If however, like me, you do not have the access to update the libraries on your system you should note that I was able to force compilation and obtain basic functionality by simply replacing the two occurrences of boost::iostreams::never_close_handle in the gnuplot-iostream.h file with 0.
I'm currently writing a very simple game engine for an assignment and to make the code a lot nicer I've decided to use a vector math library. One of my lecturers showed me the Sony Vector Math library which is used in the Bullet Physics engine and it's great as far as I can see. I've got it working on Linux nicely but I'm having problems porting it to work on OS X (intel, Snow Leopard). I have included the files correctly in my project but the C++ version of the library doesn't seem to compile. I can get the C version of the library working but it has a fairly nasty API compared to the C++ version and the whole reason of using this library was to neaten the code in the first place.
http://glosx.blogspot.com/2008/07/sony-vector-math-library.html
This blog post that I've stumbled upon seems to suggest something's up with the compiler? It's fairly short so I couldn't take a lot of information from it.
When I try to use the C++ version I get the following errors (expanded view of each error):
/usr/include/vectormath/cpp/../SSE/cpp/vectormath_aos.h:156:0
/usr/include/vectormath/cpp/../SSE/cpp/vectormath_aos.h:156:
error: '__forceinline' does not name a type
second error:
/Developer/apps/gl test/main.cpp:7:0 In file included from /Developer/apps/gl test/main.cpp
/usr/include/vectormath/cpp/vectormath_aos.h:38:0 In file included from
/usr/include/vectormath/cpp/vectormath_aos.h
/usr/include/vectormath/cpp/../SSE/cpp/vectormath_aos.h:330:0 In file included from
/usr/include/vectormath/cpp/../SSE/cpp/vectormath_aos.h
/usr/include/vectormath/cpp/../SSE/cpp/vecidx_aos.h:45:0 Expected constructor, destructor,
or type conversion before '(' token in /usr/include/vectormath/cpp/../SSE/cpp/vecidx_aos.h
Finally two errors at the end of the main.cpp file:
Expected '}' at the end of input
Expected '}' at the end of input
I've Googled my heart out but I can't seem to find any answers or anything to point me in the right direction so any help will be greatly received.
Thanks,
__forceinline is a reserved word that is supported by only a couple compilers. Clearly, your compiler does not support the __forceinline keyword and the code in question is non-portable.
A very poor workaround would be to pass a new define to your compiler that gives the keyword the correct meaning. E.g.: -D__forceinline=inline or -D__forceinline=__attribute__((always_inline)) (Thanks Paul!)
The SSE version was assumed to be only for Microsoft Visual Studio. For other platforms (Mac etc) you can use the scalar version.
Bullet\Extras\vectormathlibrary\include\vectormath\scalar\cpp
It looks like someone's fixed this up and posted a patched version in response to this very issue.
Now GCC compliant.
Which compiler are you using on OS X ? There are 4 to choose from in the standard Xcode 3.2 install and the default is gcc 4.2. You might be better off trying gcc 4.0.