Search Results

Search found 7401 results on 297 pages for 'gcc warning'.

Page 238/297 | < Previous Page | 234 235 236 237 238 239 240 241 242 243 244 245  | Next Page >

  • Compile subversion on CentOs

    - by peter
    I have downloaded, compiled and installed so far: apr-1.3.9 apr-util-1.3.9 sqlite-3.6.23 zlib-1.2.4 libtool-2.2.6b Now after downloading subversion-1.6.9, the config works fine but compiling it will end with the following error: cd subversion/svn && /bin/sh /root/subversion-1.6.9/libtool --tag=CC --silent --mode=link gcc -g -O2 -g -O2 -pthread -rpath /usr/local/lib -o svn add-cmd.o blame-cmd.o cat-cmd.o changelist-cmd.o checkout-cmd.o cleanup-cmd.o commit-cmd.o conflict-callbacks.o copy-cmd.o delete-cmd.o diff-cmd.o export-cmd.o help-cmd.o import-cmd.o info-cmd.o list-cmd.o lock-cmd.o log-cmd.o main.o merge-cmd.o mergeinfo-cmd.o mkdir-cmd.o move-cmd.o notify.o propdel-cmd.o propedit-cmd.o propget-cmd.o proplist-cmd.o props.o propset-cmd.o resolve-cmd.o resolved-cmd.o revert-cmd.o status-cmd.o status.o switch-cmd.o tree-conflicts.o unlock-cmd.o update-cmd.o util.o ../../subversion/libsvn_client/libsvn_client-1.la ../../subversion/libsvn_wc/libsvn_wc-1.la ../../subversion/libsvn_ra/libsvn_ra-1.la ../../subversion/libsvn_delta/libsvn_delta-1.la ../../subversion/libsvn_diff/libsvn_diff-1.la ../../subversion/libsvn_subr/libsvn_subr-1.la /usr/local/apr/lib/libaprutil-1.la -lexpat /usr/local/apr/lib/libapr-1.la -lrt -lcrypt -lpthread -ldl /usr/bin/ld: cannot find -lexpat collect2: ld returned 1 exit status make: * [subversion/svn/svn] Error 1 The file at /usr/local/apr/lib/libapr-1.la exists and seems to be OK (from permission perspective What could be the problem here? Thanks Peter

    Read the article

  • How to convert from hex-encoded string to a "human readable" string?

    - by John Jensen
    I'm using the Net-SNMP bindings for python and I'm attempting to grab an ARP cache from a Brocade switch. Here's what my code looks like: #!/usr/bin/env python import netsnmp def get_arp(): oid = netsnmp.VarList(netsnmp.Varbind('ipNetToMediaPhysAddress')) res = netsnmp.snmpwalk(oid, Version=2, DestHost='10.0.1.243', Community='public') return res arp_table = get_arp() print arp_table The SNMP code itself is working fine. Output from snmpwalk looks like this: <snip> IP-MIB::ipNetToMediaPhysAddress.128.10.200.6.158 = STRING: 0:1b:ed:a3:ec:c1 IP-MIB::ipNetToMediaPhysAddress.129.10.200.6.162 = STRING: 0:1b:ed:a4:ac:c1 IP-MIB::ipNetToMediaPhysAddress.130.10.200.6.166 = STRING: 0:1b:ed:38:24:1 IP-MIB::ipNetToMediaPhysAddress.131.10.200.6.170 = STRING: 74:8e:f8:62:84:1 </snip> But my output from the python script yields a tuple of hex-encoded strings that looks like this: ('\x00$8C\x98\xc1', '\x00\x1b\xed;_A', '\x00\x1b\xed\xb4\x8f\x81', '\x00$86\x15\x81', '\x00$8C\x98\x81', '\x00\x1b\xed\x9f\xadA', ...etc) I've spent some time googling and came across the struct module and the .decode("hex") string method, but the .decode("hex") method doesn't seem to work: Python 2.7.3 (default, Apr 10 2013, 06:20:15) [GCC 4.6.3] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> hexstring = '\x00$8C\x98\xc1' >>> newstring = hexstring.decode("hex") Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/usr/lib/python2.7/encodings/hex_codec.py", line 42, in hex_decode output = binascii.a2b_hex(input) TypeError: Non-hexadecimal digit found >>> And the documentation for struct is a bit over my head.

    Read the article

  • Basic compile issue with QT4

    - by Cobus Kruger
    I've been trying to get a dead simple listing from a university textbook to compile with the newest QT SDK for Windows I downloaded last night. After struggling through the regular nonsense (no make.bat, need to manually add environment variables and so on) I am finally at the point where I can build. But only one of the two libraries seem to work. The .pro file I use is dead simple: SUBDIRS += utils \ dataobjects TEMPLATE = subdirs In each of these two subfolders I have the source for a library. Running QMAKE generates a makefile and running Make runs through all the preliminaries and then fails on the g++ call: g++ -enable-stdcall-fixup -Wl,-enable-auto-import -Wl,-enable-runtime-pseudo-reloc --out-implib,libdataobjects.a -shared -mthreads -Wl -Wl,--out-implib,c:\Users\Cobus\workspace\lib\libdataobjects.a -o ..\..\lib\dataobjects.dll object_script.dataobjects.Debug -L"c:\Users\Cobus\Portab~1\Qt\2010.02.1\qt\lib" -LC:\Users\Cobus\workspace\lib -lutils -lQtXmld4 -lQtGuid4 -lQtCored4 c:/users/cobus/portab~1/qt/2010.02.1/mingw/bin/../lib/gcc/mingw32/4.4.0/../../../../mingw32/bin/ld.exe: cannot find -lutils The problem seems to be right near the end of the command line, where -lutils is added, indicating that there is a library by the name of utils. While I would have expected to see that, you'll notice the library names after --out include lib in the name, so they become libutils and libdataobjects. I have tried to figure out why this is happening, to no avail. Anyone have an idea what's going on?

    Read the article

  • Save PyML.classifiers.multi.OneAgainstRest(SVM()) object?

    - by Michael Aaron Safyan
    I'm using PYML to construct a multiclass linear support vector machine (SVM). After training the SVM, I would like to be able to save the classifier, so that on subsequent runs I can use the classifier right away without retraining. Unfortunately, the .save() function is not implemented for that classifier, and attempting to pickle it (both with standard pickle and cPickle) yield the following error message: pickle.PicklingError: Can't pickle : it's not found as __builtin__.PySwigObject Does anyone know of a way around this or of an alternative library without this problem? Thanks. Edit/Update I am now training and attempting to save the classifier with the following code: mc = multi.OneAgainstRest(SVM()); mc.train(dataset_pyml,saveSpace=False); for i, classifier in enumerate(mc.classifiers): filename=os.path.join(prefix,labels[i]+".svm"); classifier.save(filename); Notice that I am now saving with the PyML save mechanism rather than with pickling, and that I have passed "saveSpace=False" to the training function. However, I am still gettting an error: ValueError: in order to save a dataset you need to train as: s.train(data, saveSpace = False) However, I am passing saveSpace=False... so, how do I save the classifier(s)? P.S. The project I am using this in is pyimgattr, in case you would like a complete testable example... the program is run with "./pyimgattr.py train"... that will get you this error. Also, a note on version information: [michaelsafyan@codemage /Volumes/Storage/classes/cse559/pyimgattr]$ python Python 2.6.1 (r261:67515, Feb 11 2010, 00:51:29) [GCC 4.2.1 (Apple Inc. build 5646)] on darwin Type "help", "copyright", "credits" or "license" for more information. import PyML print PyML.__version__ 0.7.0

    Read the article

  • Enforce strong type checking in C (type strictness for typedefs)

    - by quinmars
    Is there a way to enforce explicit cast for typedefs of the same type? I've to deal with utf8 and sometimes I get confused with the indices for the character count and the byte count. So it be nice to have some typedefs: typedef unsigned int char_idx_t; typedef unsigned int byte_idx_t; With the addition that you need an explicit cast between them: char_idx_t a = 0; byte_idx_t b; b = a; // compile warning b = (byte_idx_t) a; // ok I know that such a feature doesn't exist in C, but maybe you know a trick or a compiler extension (preferable gcc) that does that. EDIT: I still don't really like the Hungarian notation in general, I couldn't used it for this problem because of project coding conventions, but I used it now in another similar case, where also the types are the same and the meanings are very similar. And I have to admit: it helps. I never would go and declare every integer with a starting "i", but as in Joel's example for overlapping types, it can be life saving.

    Read the article

  • Access cost of dynamically created objects with dynamically allocated members

    - by user343547
    I'm building an application which will have dynamic allocated objects of type A each with a dynamically allocated member (v) similar to the below class class A { int a; int b; int* v; }; where: The memory for v will be allocated in the constructor. v will be allocated once when an object of type A is created and will never need to be resized. The size of v will vary across all instances of A. The application will potentially have a huge number of such objects and mostly need to stream a large number of these objects through the CPU but only need to perform very simple computations on the members variables. Could having v dynamically allocated could mean that an instance of A and its member v are not located together in memory? What tools and techniques can be used to test if this fragmentation is a performance bottleneck? If such fragmentation is a performance issue, are there any techniques that could allow A and v to allocated in a continuous region of memory? Or are there any techniques to aid memory access such as pre-fetching scheme? for example get an object of type A operate on the other member variables whilst pre-fetching v. If the size of v or an acceptable maximum size could be known at compile time would replacing v with a fixed sized array like int v[max_length] lead to better performance? The target platforms are standard desktop machines with x86/AMD64 processors, Windows or Linux OSes and compiled using either GCC or MSVC compilers.

    Read the article

  • Execute a BASH command in Python-- in the same process

    - by Baldur
    I need to execute the command . /home/db2v95/sqllib/db2profile before I can import ibm_db_dbi in Python 2.6. Executing it before I enter Python works: baldurb@gigur:~$ . /home/db2v95/sqllib/db2profile baldurb@gigur:~$ python Python 2.6.4 (r264:75706, Dec 7 2009, 18:45:15) [GCC 4.4.1] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> import ibm_db_dbi >>> but executing it in Python using os.system(". /home/db2v95/sqllib/db2profile") or subprocess.Popen([". /home/db2v95/sqllib/db2profile"]) results in an error. What am I doing wrong? Edit: this is the error I receive: > Traceback (most recent call last): > File "<file>.py", line 8, in > <module> > subprocess.Popen([". /home/db2v95/sqllib/db2profile"]) > File > "/usr/lib/python2.6/subprocess.py", > line 621, in __init__ > errread, errwrite) File "/usr/lib/python2.6/subprocess.py", > line 1126, in _execute_child > raise child_exception OSError: [Errno 2] No such file or directory

    Read the article

  • ffmpeg mp3 convertion

    - by Alex
    was to convert several thousand MP3 files, and get this for some files: ffmpeg -t 45 -i "public/system/musics/files/2009/original/03_Memphis.mp3" -y "memphis.mp3" FFmpeg version 0.5-svn17737+3:0.svn20090303-1ubuntu6, Copyright (c) 2000-2009 Fabrice Bellard, et al. configuration: --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --extra-version=svn17737+3:0.svn20090303-1ubuntu6 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --disable-stripping --disable-vhook --enable-libdc1394 --disable-armv5te --disable-armv6 --disable-armv6t2 --disable-armvfp --disable-neon --disable-altivec --disable-vis --enable-shared --disable-static libavutil 49.15. 0 / 49.15. 0 libavcodec 52.20. 0 / 52.20. 0 libavformat 52.31. 0 / 52.31. 0 libavdevice 52. 1. 0 / 52. 1. 0 libavfilter 0. 4. 0 / 0. 4. 0 libswscale 0. 7. 1 / 0. 7. 1 libpostproc 51. 2. 0 / 51. 2. 0 built on Apr 10 2009 23:18:41, gcc: 4.3.3 public/system/musics/files/2009/original/03_Memphis.mp3: could not find codec parameters what could be the problem?

    Read the article

  • Diamond problem in C++

    - by Jack
    I know the diamond problem. I am using gcc compiler. I have some scenarios I need explanation about. 1) class A{ public: virtual void eat(){cout<<"A eat\n";} }; class B:public A{ public: void eat(){ cout<<"B eat\n";}}; class C:public A{ public: void eat(){ cout<<"C eat\n";}}; class D:public B,C{ public: void eat(){ cout<<"D eat\n";}}; int main() { A * a = new D(); a->eat(); getch(); return 0; } Why doesn't this work? 2) class A{ public: void eat(){cout<<"A eat\n";} }; class B:virtual public A{ public: void eat(){ cout<<"B eat\n";}}; class C:virtual public A{ public: void eat(){ cout<<"C eat\n";}}; class D: public B,C{ public: void eat(){ cout<<"D eat\n";}}; int main() { A * a = new D(); a->eat(); getch(); return 0; } When I do this what happens in the background. How does the ambiguity get removed. Is the concept of vtables involved here?

    Read the article

  • Simple jQuery code contains a syntax error that I can't find

    - by inkedmn
    I've got this (remarkably) simple JavaScript function that is called when a user clicks a "Cancel" link: function hideNewUserPanel(){ $('#create_user_panel').slideUp('slow'); $('.right_interior_panel').slideDown('slow'); } And the code to add the handler: $(function(){ $('#cancel_create_user_btn').live('click', function(){ hideNewUserPanel(); } }); Functionally, everything works as expected. Trouble is, when I click the "Cancel" link, Firebug shows an error in the console: uncaught exception: Syntax error, unrecognized expression: # I've stepped through the code several times and the error appears at some point before the call to hideNewUserPanel(). At the risk of sounding like one of "those programmers" (the kind that claim to have found a bug in GCC and assume their own code is perfect), the exception is being thrown from somewhere within jQuery proper, so I assume the issue is in there. I'm using jQuery 1.3.2 (this is a legacy project using many jQuery plugins that will break if we update to 1.4.x). Is there anything obviously wrong with my code that I'm simply not seeing? This code is, frankly, very simple and I don't really see what the issue could be. Thanks!

    Read the article

  • Moving inserted container element if possible

    - by doublep
    I'm trying to achieve the following optimization in my container library: when inserting an lvalue-referenced element, copy it to internal storage; but when inserting rvalue-referenced element, move it if supported. The optimization is supposed to be useful e.g. if contained element type is something like std::vector, where moving if possible would give substantial speedup. However, so far I was unable to devise any working scheme for this. My container is quite complicated, so I can't just duplicate insert() code several times: it is large. I want to keep all "real" code in some inner helper, say do_insert() (may be templated) and various insert()-like functions would just call that with different arguments. My best bet code for this (a prototype, of course, without doing anything real): #include <iostream> #include <utility> struct element { element () { }; element (element&&) { std::cerr << "moving\n"; } }; struct container { void insert (const element& value) { do_insert (value); } void insert (element&& value) { do_insert (std::move (value)); } private: template <typename Arg> void do_insert (Arg arg) { element x (arg); } }; int main () { { // Shouldn't move. container c; element x; c.insert (x); } { // Should move. container c; c.insert (element ()); } } However, this doesn't work at least with GCC 4.4 and 4.5: it never prints "moving" on stderr. Or is what I want impossible to achieve and that's why emplace()-like functions exist in the first place?

    Read the article

  • Throwing a C++ exception after an inline-asm jump

    - by SoapBox
    I have some odd self modifying code, but at the root of it is a pretty simple problem: I want to be able to execute a jmp (or a call) and then from that arbitrary point throw an exception and have it caught by the try/catch block that contained the jmp/call. But when I do this (in gcc 4.4.1 x86_64) the exception results in a terminate() as it would if the exception was thrown from outside of a try/catch. I don't really see how this is different than throwing an exception from inside of some far-flung library, yet it obviously is because it just doesn't work. How can I execute a jmp or call but still throw an exception back to the original try/catch? Why doesn't this try/catch continue to handle these exceptions as it would if the function was called normally? The code: #include <iostream> #include <stdexcept> using namespace std; void thrower() { cout << "Inside thrower" << endl; throw runtime_error("some exception"); } int main() { cout << "Top of main" << endl; try { asm volatile ( "jmp *%0" // same thing happens with a call instead of a jmp : : "r"((long)thrower) : ); } catch (exception &e) { cout << "Caught : " << e.what() << endl; } cout << "Bottom of main" << endl << endl; } The expected output: Top of main Inside thrower Caught : some exception Bottom of main The actual output: Top of main Inside thrower terminate called after throwing an instance of 'std::runtime_error' what(): some exception Aborted

    Read the article

  • Template compiling errors on iPhone SDK 3.2

    - by Didier Malenfant
    I'm porting over some templated code from Windows and I'm hitting some compiler differences on the iPhone 3.2 SDK. Original code inside a class template's member function is: return BinarySearch<uint32, CSimpleKey<T> >(key); where BinarySearch is a method inherited from another template. This produces the following error: csimplekeytable.h:131: error: no matching function for call to 'BinarySearch(NEngine::uint32&)' The visual studio compiler seems to walk up the template hierarchy fine but gcc needs me to fully qualify where the function comes from (I have verified this by fixing the same issues with template member variables that way). So I now need to change this into: return CSimpleTable<CSimpleKey<T> >::BinarySearch<uint32, CSimpleKey<T> >(key); Which now produces the following error: csimplekeytable.h:132: error: expected primary-expression before ',' token csimplekeytable.h:132: error: expected primary-expression before '>' token After some head scratching, I believe what's going on here is that it's trying to resolve the '<' before BinarySearch as a 'Less Than' operator for some reason. So two questions: - Am I on the right path with my interpretation of the error? - How do I fix it? -D

    Read the article

  • How to link pnglite library in c?

    - by zaplec
    Hi, I installed from kubuntu's package management this handy pnglite library. It contains just one header file "pnglite.h" and one object file "pnglite.o". I have found out where those files are, but I don't know how to link them. I'm using netbeans, but don't know how to link them in there. Also I don't understand how to link them at console. I have a little test program that I would like to test, but I get the error message "undefined reference to function: XXXXXXX". Both netbeans and at console I'm using gcc. That header file is in /usr/include directory, object file is in /usr/lib directory and my test program is under my programming directory at my home directory. Should I put that header and object into the same directory as where my source is? Or is there a way to link them from their current locations? I know that it should be possible to link them from where they are at the moment and I would like to know and understand how to do that. Any help will be appreciated :)

    Read the article

  • Is it possible to declare multiple static variable with same name in a single C file?

    - by Mohammed Khalid Kherani
    Hi Experts, Is it possible to declare multiple static variables of same name in a single C file with different scopes? I wrote a simple programme to check this and in gcc it got compiled and worked fine. code: static int sVar = 44; void myPrint2() { printf("sVar = %d\n", sVar++); } void myPrint() { static int sVar =88; printf("sVar = %d\n", sVar++); } int main(void) { static int sVar = 55; int i = 0; for (i = 0; i < 5; i++) myPrint(); printf("sVar = %d\n", sVar); myPrint2(); return(0); } Now my question is since all "static" variable will reside in same section (.data) then how we can have multiple variable with same name in one section? I used objdump to check the different section and found that all Static variables (sVar) were in .data section but with different names 0804960c l O .data 00000004 sVar 08049610 l O .data 00000004 sVar.1785 08049614 l O .data 00000004 sVar.1792 Why compiler is changing the name of variables (since C doesnt support name mangling)? Thanks in advance.

    Read the article

  • x86_64 assembler: only one call per subroutine?

    - by zneak
    Hello everyone, I decided yesterday to start doing assembler. Most of it is okay (well, as okay as assembler can be), but I'm getting some problems with gas. It seems that I can call functions only once. After that, any subsequent call opcode with the same function name will fail. I must be doing something terribly wrong, though I can't see what. Take this small C function for instance: void path_free(path_t path) { if (path == NULL) return; free(((point_list_t*)path)->points); free(path); } I "translated" it to assembler like that: .globl _path_free _path_free: push rbp mov rbp, rsp cmp rdi, 0 jz byebye push rdi mov rdi, qword ptr [rdi] call _free pop rdi sub rsp, 8 call _free byebye: leave ret This triggers the following error for the second call _free: suffix or operands invalid for ``call''. And if I change it to something else, like free2, everything works (until link time, that is). Assembler code gcc -S gave me looks very similar to what I've done (except it's in AT&T syntax), so I'm kind of lost. I'm doing this on Mac OS X under the x86_64 architecture.

    Read the article

  • derived class as default argument g++

    - by Vincent
    Please take a look at this code: template<class T> class A { class base { }; class derived : public A<T>::base { }; public: int f(typename A<T>::base& arg = typename A<T>::derived()) { return 0; } }; int main() { A<int> a; a.f(); return 0; } Compiling generates the following error message in g++: test.cpp: In function 'int main()': test.cpp:25: error: default argument for parameter of type 'A<int>::base&' has type 'A<int>::derived' The basic idea (using derived class as default value for base-reference-type argument) works in visual studio, but not in g++. I have to publish my code to the university server where they compile it with gcc. What can I do? Is there something I am missing?

    Read the article

  • Potential g++ template bug?

    - by Evan Teran
    I've encountered some code which I think should compile, but doesn't. So I'm hoping some of the local standards experts here at SO can help :-). I basically have some code which resembles this: #include <iostream> template <class T = int> class A { public: class U { }; public: U f() const { return U(); } }; // test either the work around or the code I want... #ifndef USE_FIX template <class T> bool operator==(const typename A<T>::U &x, int y) { return true; } #else typedef A<int> AI; bool operator==(const AI::U &x, int y) { return true; } #endif int main() { A<int> a; std::cout << (a.f() == 1) << std::endl; } So, to describe what is going on here. I have a class template (A) which has an internal class (U) and at least one member function which can return an instance of that internal class (f()). Then I am attempting to create an operator== function which compares this internal type to some other type (in this case an int, but it doesn't seem to matter). When USE_FIX is not defined I get the following error: test.cc: In function 'int main()': test.cc:27:25: error: no match for 'operator==' in 'a.A<T>::f [with T = int]() == 1' Which seems odd, because I am clearly (I think) defining a templated operator== which should cover this, in fact if I just do a little of the work for the compiler (enable USE_FIX), then I no longer get an error. Unfortunately, the "fix" doesn't work generically, only for a specific instantiation of the template. Is this supposed to work as I expected? Or is this simply not allowed? BTW: if it matters I am using gcc 4.5.2.

    Read the article

  • Should i enforce realloc check if the new block size is smaller than the initial ?

    - by nomemory
    Can realloc fail in this case ? int *a = NULL; a = calloc(100, sizeof(*a)); printf("1.ptr: %d \n", a); a = realloc(a, 50 * sizeof(*a)); printf("2.ptr: %d \n", a); if(a == NULL){ printf("Is it possible?"); } return (0); } The output in my case is: 1.ptr: 4072560 2.ptr: 4072560 So 'a' points to the same adress. So should i enforce realloc check ? Later edit: Using MinGW compiler under Windows XP. Is the behaviour similar with gcc on Linux ? Later edit 2: Is it OK to check this way ? int *a = NULL, *b = NULL; a = calloc(100, sizeof(*a)); b = realloc(a, 50 * sizeof(*a)); if(b == NULL){ return a; } a = b; return a;

    Read the article

  • How do I configure multiple Ubuntu Python installations to avoid App Engine's SSL error?

    - by Linc
    I have Karmic Koala which has Python 2.6 installed by default. However I can't run any Python App Engine projects because they require Python 2.5 and python ssl. To install ssl I installed python2.5-dev first while following some instructions I found elsewhere. sudo apt-get install libssl-dev sudo apt-get install python-setuptools sudo apt-get install python2.5-dev sudo easy_install-2.5 pyopenssl However, I am afraid this is not good for my Ubuntu installation since Ubuntu expects to see version 2.6 of Python when you type 'python' on the command line. Instead, it says '2.5.5'. I tried to revert to the original default version of Python by doing this: sudo apt-get remove python2.5-dev But that didn't seem to do anything either - when I type 'python' on the command line it still say 2.5.5. And App Engine still doesn't work after all this. I continue to get an SSL-related error whenever I try to run my Python app: AttributeError: 'module' object has no attribute 'HTTPSHandler' UPDATE: Just checked whether SSL actually installed as a result of those commands by typing this: $ python2.5 Python 2.5.5 (r255:77872, Apr 29 2010, 23:59:20) [GCC 4.4.1] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> import ssl Traceback (most recent call last): File "<stdin>", line 1, in <module> ImportError: No module named ssl >>> As you can see, SSL is still not installed, which explains the continuing App Engine error. If anyone knows how I can dig myself out of this hole, I would appreciate it.

    Read the article

  • Constructor and Destructors in C++ [Not a question] [closed]

    - by Jack
    I am using gcc. Please tell me if I am wrong - Lets say I have two classes A & B class A { public: A(){cout<<"A constructor"<<endl;} ~A(){cout<<"A destructor"<<endl;} }; class B:public A { public: B(){cout<<"B constructor"<<endl;} ~B(){cout<<"B destructor"<<endl;} }; 1) The first line in B's constructor should be a call to A's constructor ( I assume compiler automatically inserts it). Also the last line in B's destructor will be a call to A's destructor (compiler does it again). Why was it built this way? 2) When I say A * a = new B(); compiler creates a new B object and checks to see if A is a base class of B and if it is it allows 'a' to point to the newly created object. I guess that is why we don't need any virtual constructors. ( with help from @Tyler McHenry , @Konrad Rudolph) 3) When I write delete a compiler sees that a is an object of type A so it calls A's destructor leading to a problem which is solved by making A's destructor virtual. As user - Little Bobby Tables pointed out to me all destructors have the same name destroy() in memory so we can implement virtual destructors and now the call is made to B's destructor and all is well in C++ land. Please comment.

    Read the article

  • template style matrix implementation in c

    - by monkeyking
    From time to time I use the following code for generating a matrix style datastructure typedef double myType; typedef struct matrix_t{ |Compilation started at Mon Apr 5 02:24:15 myType **matrix; | size_t x; |gcc structreaderGeneral.c -std=gnu99 -lz size_t y; | }matrix; |Compilation finished at Mon Apr 5 02:24:15 | | matrix alloc_matrix(size_t x, size_t y){ | if(0) | fprintf(stderr,"\t-> Alloc matrix with dim (%lu,%lu) byteprline=%lu bytetotal:%l\| u\n",x,y,y*sizeof(myType),x*y*sizeof(myType)); | | myType **m = (myType **)malloc(x*sizeof(myType **)); | for(size_t i=0;i<x;i++) | m[i] =(myType *) malloc(y*sizeof(myType *)); | | matrix ret; | ret.x=x; | ret.y=y; | ret.matrix=m; | return ret; | } And then I would change my typedef accordingly if I needed a different kind of type for the entries in my matrix. Now I need 2 matrices with different types, an easy solution would be to copy/paste the code, but is there some way to do a template styled implementation. Thanks

    Read the article

  • Mac OS X and static boost libs -> std::string fail

    - by Ionic
    Hi all, I'm experiencing some very weird problems with static boost libraries under Mac OS X 10.6.6. The error message is main(78485) malloc: *** error for object 0x1000e0b20: pointer being freed was not allocated *** set a breakpoint in malloc_error_break to debug [1] 78485 abort (core dumped) and a tiny bit of example code which will trigger this problem: #define BOOST_FILESYSTEM_VERSION 3 #include <boost/filesystem.hpp> #include <iostream> int main (int argc, char **argv) { std::cout << boost::filesystem::current_path ().string () << '\n'; } This problem always occurs when linking the static boost libraries into the binary. Linking dynamically will work fine, though. I've seen various reports for quite a similar OS X bug with GCC 4.2 and the _GLIBCXX_DEBUG macro set, but this one seems even more generic, as I'm neither using XCode, nor setting the macro (even undefining it does not help. I tried it just to make sure it's really not related to this problem.) Does anybody have any pointers to why this is happening or even maybe a solution (rather than using the dynamic library workaround)? Best regards, Mihai

    Read the article

  • How is it legal to reference an undefined type inside a structure?

    - by paxdiablo
    As part of answering another question, I came across a piece of code like this, which gcc compiles without complaint. typedef struct { struct xyz *z; } xyz; int main (void) { return 0; } This is the means I've always used to construct types that point to themselves (e.g., linked lists) but I've always thought you had to name the struct so you could use self-reference. In other words, you couldn't use xyz *z within the structure because the typedef is not yet complete at that point. But this particular sample does not name the structure and it still compiles. I thought originally there was some black magic going on in the compiler that automatically translated the above code because the structure and typedef names were the same. But this little beauty works as well: typedef struct { struct NOTHING_LIKE_xyz *z; } xyz; What am I missing here? This seems a clear violation since there is no struct NOTHING_LIKE_xyz type defined anywhere. When I change it from a pointer to an actual type, I get the expected error: typedef struct { struct NOTHING_LIKE_xyz z; } xyz; qqq.c:2: error: field `z' has incomplete type Also, when I remove the struct, I get an error (parse error before "NOTHING ...). Is this allowed in ISO C?

    Read the article

  • fesetround with MSVC x64

    - by mr grumpy
    I'm porting some code to Windows (sigh) and need to use fesetround. MSVC doesn't support C99, so for x86 I copied an implementation from MinGW and hacked it about: //__asm__ volatile ("fnstcw %0;": "=m" (_cw)); __asm { fnstcw _cw } _cw &= ~(FE_TONEAREST | FE_DOWNWARD | FE_UPWARD | FE_TOWARDZERO); _cw |= mode; //__asm__ volatile ("fldcw %0;" : : "m" (_cw)); __asm { fldcw _cw } if (has_sse) { unsigned int _mxcsr; //__asm__ volatile ("stmxcsr %0" : "=m" (_mxcsr)); __asm { stmxcsr _mxcsr } _mxcsr &= ~ 0x6000; _mxcsr |= (mode << __MXCSR_ROUND_FLAG_SHIFT); //__asm__ volatile ("ldmxcsr %0" : : "m" (_mxcsr)); __asm { ldmxcsr _mxcsr } } The commented lines are the originals for gcc; uncommented for msvc. This appears to work. However the x64 cl.exe doesn't support inline asm, so I'm stuck. Is there some code out there I can "borrow" for this? (I've spent hours with Google). Or will I have to go on a 2 week detour to learn some assembly and figure out how to get/use MASM? Any advice is appreciated. Thank you.

    Read the article

< Previous Page | 234 235 236 237 238 239 240 241 242 243 244 245  | Next Page >