📚 LinuxDocs
Topics:
All Pages8021X HOWTOACP ModemACPI HOWTOADSL Bandwidth Man..ATA RAID HOWTOATM Linux HOWTOAX25 HOWTOAccessibility Dev ..Accessibility HOWTOAdv Bash Scr HOWTOAdv Routing HOWTOAntares RAID sparc..Apache Compile HOWTOApache WebDAV LDAP..Assembly HOWTOAstronomy HOWTOAthlon Powersaving..Authentication Gat..Autodir HOWTOAviation HOWTOAvr Microcontrolle..BRIDGE STP HOWTOBTTVBackspaceDeleteBandwidth Limiting..Bangla HOWTOBash Prompt HOWTOBattery PoweredBelarusian HOWTOBelgian HOWTOBeowulf HOWTOBocaBogoMipsBootdisk HOWTOBridgeC++ dlopenC C++Beautifier HO..C editing with VIM..CDROM HOWTOCDServer HOWTOCable ModemCaudium HOWTOClone HOWTOCompaq Remote Insi..Compaq T1500 HOWTOConexant+Rockwell ..Cryptoloop HOWTODB2 HOWTODHCPDSL HOWTODVD Playback HOWTODebian Binary Pack..Debian JigdoDebian and Windows..Disk Encryption HO..Disk on Chip HOWTODocBook Demystific..DocBook InstallDocBook OpenJade S..Ecology HOWTOEmacspeak HOWTOEncourage Women Li..Encrypted Root Fil..Euro Char SupportEvent HOWTOFedora Multimedia ..Finnish HOWTOFirewall PiercingFlash Memory HOWTOFont HOWTOFramebuffer HOWTOGCC HOWTOGIS GRASSGlibc Install HOWTOHOWTO HOWTOHOWTO INDEXHP HOWTOHandspring VisorHard Disk UpgradeHardware HOWTOHighQuality Apps H..Home Electrical Co..IBM7248 HOWTOIO Perf HOWTOIP AliasIP Masquerade HOWTOIRCImplement Sys Call..Indic Fonts HOWTOInfrared HOWTOIngresII HOWTOInstall StrategiesInstallation HOWTOInstallfest HOWTOIntkeybItalian HOWTOJabber Server Farm..JavaStation HOWTOKerberos Infrastru..Kernel HOWTOKerneldKodak Digitalcam H..LDAP HOWTOLDP Reviewer HOWTOLILO crash rescue ..LVM HOWTOLeased LineLegoLinksys Blue Box R..Linux+Win95Linux+Win9x+Grub H..Linux+Windows HOWTOLinux Complete Bac..Linux Crash HOWTOLinux Gamers HOWTOLinux Modem SharingLinux Promise RAID..Linux i386 Boot Co..LinuxGL QuakeWorld..Lotus DominoR5MILO HOWTOMMBase Inst HOWTOMP3 CD BurningMail User HOWTOMajordomo MajorCoo..Man PageMasquerading Simpl..Medicine HOWTOMindTerm SSH HOWTOMobile IPv6 HOWTOMock MainframeModule HOWTOModulesMotorola Surfboard..Mozilla OptimizationMulti Distro DevNCURSES Programmin..NFS HOWTONFS Root Client mi..NIS HOWTONetMeeting HOWTONetwork boot HOWTONvidia OpenGL Conf..OLSR IPv6 HOWTOOnline Troubleshoo..Oracle 9i Fedora 3..PA RISC Linux Boot..PCTel MicroModem C..PHP Nuke HOWTOPPP HOWTOPagerPalmOS HOWTOPartitionPartition Mass Sto..Partition Mass Sto..Partition RescuePine ExchangePortSlavePost Installation ..Postfix Cyrus Web ..Pre Installation C..Print2WinPrinting HOWTOProcess AccountingProgram Library HO..Proxy ARP SubnetQmail ClamAV HOWTOQmail VMailMgr Cou..Querying libiptc H..RPM HOWTOReading List HOWTORedHat CD HOWTOReliance HOWTORemote BridgingRemote Serial Cons..SCSI 2.4 HOWTOSCSI Generic HOWTOSLIP PPP EmulatorSRM HOWTOSSL Certificates H..Scanner HOWTOScientific Computi..Scripting GUI TclTkSecure CVS PserverSecure Programs HO..Security HOWTOSecurity Quickstar..Security Quickstar..Serial Laplink HOWTOSerial Programming..Slovak HOWTOSmall MemorySmart Card HOWTOSoftware Proj Mgmt..Software Release P..Sound HOWTOSpam Filtering for..Speech Recognition..SquashFS HOWTOSybase ASA HOWTOSybase ASE HOWTOSybase PHP ApacheTCP Keepalive HOWTOTamil Linux HOWTOTimePrecision HOWTOTimeSys Linux Inst..Token RingTraffic Control HO..Traffic Control tc..UPS HOWTOUnix Hardware Buye..Unix and Internet ..UpgradeUsenet News HOWTOUser Authenticatio..VB6 to TclVMS to Linux HOWTOVPN HOWTOValgrind HOWTOVideoLAN HOWTOVim HOWTOVirtual WebWebcam HOWTOWikiText HOWTOWindows Newsreader..Wireless Link sys ..Wireless Sync HOWTOXDM XtermXDMCP HOWTOXFree Local multi ..XFree86 HOWTOXFree86 R200XFree86 Second MouseXFree86 Video Timi..XML RPC HOWTOXWindow Overview H..XWindow User HOWTOXinerama HOWTOXterminalsHtml singleI810 HOWTOLibdc1394 HOWTOOpenMosix HOWTOPhhttpd HOWTOPpp sshText

2. The Problem

At some time you might have to load a library (and use its functions) at runtime; this happens most often when you are writing some kind of plug-in or module architecture for your program.

In the C language, loading a library is very simple (calling dlopen, dlsym and dlclose is enough), with C++ this is a bit more complicated. The difficulties of loading a C++ library dynamically are partially due to .:: www.just.edu.jo ::. .:: telegra.ph ::. name mangling, and partially due to the fact that the dlopen API was written with C in mind, thus not offering a suitable way to load classes.

Before explaining how to load libraries in C++, let's better analyze the problem by looking at name mangling in more detail. I recommend you read the explanation of name mangling, even if you're not interested in it because it will help you understanding why problems occur and how to solve them.

2.1. Name Mangling

In every C++ program (or library, or object file), all non-static functions are represented in the binary file as .:: podcasts.apple.com ::. .:: www.mobafire.com ::. symbols. These symbols are special text strings that uniquely identify a function in the program, library, or object file.

In C, the symbol name is the same as the function name: the symbol of strcpy will be strcpy, and so on. This is possible because in C no two non-static functions can have the same name. .:: link-indexing-checker.vercel.app ::.

Because C++ allows overloading (different functions with the same name but different arguments) and has many features C does not — like classes, member functions, exception specifications — it is not possible to simply use the function name as the symbol name. To solve that, C++ uses so-called name mangling, which transforms the function name and all the necessary information (like the number and size of the arguments) into some weird-looking string which only the compiler knows about. The mangled name of foo might look like foo@4%6^, for example. Or it might not even contain the word "foo".

One of the problems with name mangling is that the C++ standard (currently [ [r/Pandas Topics] ISO14882]) does not define how names have to be mangled; thus every compiler mangles names in its own way. Some compilers even change their name mangling algorithm between different versions (notably g++ 2.x and 3.x). Even if you worked out how your particular compiler mangles names (and would thus be able to load functions via .:: www.outdooractive.com ::. dlsym), this would most probably work with your compiler only, and might already be broken with the next version. .:: www.fiskesnack.com ::.

2.2. Classes

Another problem with the dlopen API is the fact that it only supports loading functions. But in C++ a library often exposes a class which you would like to use in your program. Obviously, to use that class you need to create an instance of it, but that cannot be easily done. [Reference: Docker]

Share or Research:

Share on FB Post to X LinkedIn 🤖 Ask AI about this