Clang Error Reference To Non-static Member Function Must Be Called
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Reference To Non-static Member Function Must Be Called Sort
Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; it reference to non-static member function must be called c++11 only takes a minute: Sign up Unable to call a template member function of a template class from another template class up vote 5 down vote favorite I'm getting compiler errors when attempting to access a template member function of reference to non-static member function must be called template a template class from within another template class. A function call to getSubmatrix results in the compiler warnings, "expression result unused", about the parameters (0, 0), finally failing with the compiler error "reference to non-static member function must be called". The matrix class: template class Matrix { public: ... template Matrix& getSubmatrix(std::size_t column, std::size_t row) { ... } }; The transform
Cannot Create A Non-constant Pointer To Member Function
class: template class Transform { public: ... Matrix<4, 4, T> matrix() const { ... Matrix<4, 4, T> result; result.getSubmatrix<3, 3>(0, 0) = Matrix<3, 3, T>(); ... } }; Note that changing the matrix type to Matrix<4, 4, float> rather than Matrix<4, 4, T> will result in valid compilation. The compiler is clang 4.0 and the language version is C++11. c++ templates share|improve this question asked May 4 '13 at 2:13 Chris Howard 905 1 Thank you very much for this entry, this one was extremely tricky to infer from Clang error message indeed. –Ad N Aug 27 '14 at 15:05 add a comment| 1 Answer 1 active oldest votes up vote 9 down vote accepted You should add keyword template: result.template getSubmatrix<3, 3>(0, 0) = Matrix<3, 3, T>(); // ^^^^^^^^ Without it, compiler will think that < is a comparison operator. PS. In that case, g++ produces a little more understandable error: error: invalid operands of types and int to binary operator< share|improve this answer edited May 4 '13 at 2:56 Community♦ 11 answered May 4 '13 at 2:20 soon 15.2k33159 Thank you so much! –Chris Howard May 4 '13 at 2:46 2 Gosh, C++ template syntax is so intuitive. –dan-man Jan 14 '15 at 15:52 It's almost as someone invented template syntax way later in making the language specs... :P –Per Alexandersson J
[x] New user self-registration is currently disabled. Please email llvm-admin@lists.llvm.org if you need an account. First Last Prev Next This bug is not in your last search results. Bug18995 - Strangely worded error message "reference to non-static member function must be called" Summary: Strangely worded error message "reference to non-static member function must ... Status: NEW Product: clang Classification: Unclassified Component: C++ Version: 3.4 Platform: Macintosh http://stackoverflow.com/questions/16369912/unable-to-call-a-template-member-function-of-a-template-class-from-another-templ MacOS X Importance: P normal Assigned To: Unassigned Clang Bugs URL: Keywords: Depends on: Blocks: Show dependency tree /graph Reported: 2014-02-27 15:35 CST by Erik Schnetter Modified: 2015-12-10 11:58 CST (History) CC List: 4 users (show) davejohansen dgregor llvm-bugs richard-llvm See Also: Attachments Add an attachment (proposed patch, testcase, etc.) Note https://llvm.org/bugs/show_bug.cgi?id=18995 You need to log in before you can comment on or make changes to this bug. Description Erik Schnetter 2014-02-27 15:35:55 CST I received the following error message for C++ code: {{{ reference to non-static member function must be called static_cast(this)->eigenvalues( }}} The caret points to the "e" of "eigenvalues". Although I am familiar with C++, I do not understand the wording of this error message. I think the wording can be improved. The immediate meaning seems to be that there is a non-static member function, and that one must call it, implying that I am trying to do something else with it. That is wrong; I am actually trying to call it. I assume that this message wants to say "This looks like a function call for a non-static member function, but this is not actually a non-static member function." Additionally, it could tell me what "eigenvalues" actually is. In this case, the issue is
[Bug c++/65188] New: diagnostic: missing: reference to non-static member function must be called From: "jan.kratochvil at redhat dot com" https://gcc.gnu.org/ml/gcc-bugs/2015-02/msg02604.html dot gnu dot org> To: gcc-bugs at gcc dot gnu dot org Date: Tue, 24 Feb 2015 10:24:16 +0000 Subject: [Bug c++/65188] New: diagnostic: http://answers.ros.org/question/160386/c-how-to-set-a-callback-to-point-to-a-non-static-member-function-of-an-object-instance/ missing: reference to non-static member function must be called Auto-submitted: auto-generated https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65188 Bug ID: 65188 Summary: diagnostic: missing: reference to non-static member function must member function be called Product: gcc Version: 5.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: jan.kratochvil at redhat dot com Target: x86_64-linux-gnu class C { public: void f() {} } c; int main() { return c.f.a; } -Wall g++ (GCC) 5.0.0 20150224 (experimental) reference to non-static ------------------------------------------------------------------------------- 10.C: In function âint main()â: 10.C:2:21: error: âc.C::fâ does not have class type int main() { return c.f.a; } ^ ------------------------------------------------------------------------------- clang-3.5.0-6.fc21.x86_64 ------------------------------------------------------------------------------- 10.C:2:23: error: reference to non-static member function must be called; did you mean to call it with no arguments? int main() { return c.f.a; } ~~^ () 10.C:2:24: error: member reference base type 'void' is not a structure or union int main() { return c.f.a; } ~~~^~ 2 errors generated. ------------------------------------------------------------------------------- I had no idea what GCC errors on until I asked clang. It may be obvious here but with complicated classes the better error message is really helpful. Follow-Ups: [Bug c++/65188] improve error for member operator applied to non-class type From: manu at gcc dot gnu.org [Bug c++/65188] improve error for member operator applied to non-class type From: jan.kratochvil at redhat dot com Index Nav: [DateIndex] [SubjectIndex] [AuthorIndex] [ThreadIndex] Mess
asked 2014-05-04 02:50:41 -0500 Nap 123 ●16 ●22 ●28 [Ubuntu 13.10, Hydro Desktop-Full from source, C++] I am having difficulty setting up callback functions for my ROS Topic subscribers, and would appreciate help. Since all my Topics use the std_msgs::String type, I've defined the class shown below with a generic callback function and an instance variable which identifies the specific Topic. class myCallback { const char * eventtype; public: myCallback(const char * eventType) : eventtype(eventType) {} void generic_callback(const std_msgs::String::ConstPtr& msg) { std::cerr << this->eventtype << " heard: " << msg->data.c_str() << std::endl; } }; For the ROS functionality in my project, I've created a separate class gwrbclass.cpp & gwrbclass.h, which include the myCallback class. In the header file, I define myCallback *callbackList[NUM_EVENT_TYPES] as a private variable. In the implementation, I instantiate the required myCallback objects for each entry in the callbackList and try to bind it to the node's subscriber object as shown below: for (int j=0; jsubscribe(eventName, 1000, callbackList[j]->generic_callback); << ERROR OCCURRING HERE } I'm getting an error stating : reference to non-static member function must be called , and as far as I can see, the method I'm calling is not static and therefore should work. If I use subList[j] = (sNode[j])->subscribe(...., &callbackList[j]->generic_callback); the error becomes : cannot create a non-constant pointer to member function. I'm confused as to why I'm getting this error (which I believe has something to do with std::bind, function typedef, wrapper functions, etc), and would appreciate some help as I can't figure out the syntax. edit retag flag offensive close merge delete add a comment 1 answer Sort by ยป oldest newest most voted 2 answered 2014-05-04 08:41:27 -0500 fergs 11151 ●51 ●92 ●161 http://www.showus