{"id":80,"date":"2011-10-12T00:19:26","date_gmt":"2011-10-11T15:19:26","guid":{"rendered":"http:\/\/nextstep.onionmixer.net\/wordpress\/?p=80"},"modified":"2011-10-13T16:18:49","modified_gmt":"2011-10-13T07:18:49","slug":"appledata-1436-mixing-objective-c-and-c-code","status":"publish","type":"post","link":"http:\/\/nextstep.onionmixer.net\/wordpress\/?p=80","title":{"rendered":"NeXTanswers :: 1436 :: mixing objective-C and C code"},"content":{"rendered":"

Q: \u00a0How does one mix C and Objective-C code? \u00a0How can one call Objective-C from C?
\n\uc5b4\ub5bb\uac8c\ud558\uba74 Objective \ucf54\ub4dc\uc640 C\ub97c \uac19\uc774 \uc4f8 \uc218 \uc788\ub098\uc694? \uc5b4\ub5bb\uac8c C\uc5d0\uc11c Objective C\ub97c\u00a0\ud638\ucd9c\ud560 \uc218 \uc788\ub098\uc694?\u00a0<\/span><\/p>\n

A: \u00a0Just do it! \u00a0C functions can freely send Objective-C messages, and Objective-C methods can freely call C functions. \u00a0 For an example, look at main() <\/strong>of one of the applications in \/NextDeveloper\/Examples.
\n\uc77c\ub2e8 \ud574\ubcf4\uc138\uc694! C\ud568\uc218\ub294 Objective C \uba54\uc138\uc9c0\ub97c \uc804\ub2ec \ud560 \uc218 \uc788\uace0, Objective C \uba54\uc18c\ub4dc\ub294 \uc790\uc720\ub86d\uac8c C\ud568\uc218\ub97c \ud638\ucd9c\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc608\uc81c\ub4e4\uc774 \uc788\uc2b5\ub2c8\ub2e4.\u00a0\/NextDeveloper\/Examples \uc5d0 \ub4e4\uc5b4\uc788\ub294 \uc5b4\ud50c\ub9ac\ucf00\uc774\uc158\ub4e4\uc758 main()\uc744 \ubcf4\uc138\uc694.<\/span><\/p>\n

If you place Objective-C code in a “.c” file, \u00a0you need to compile the file with the Objective -C option. \u00a0The simplest way to do this is to change the “.c” suffix to “.m”, and then add the file name under “.m (other)” \u00a0in InterfaceBuilder’s Project Inspector. \u00a0 \u00a0If it’s not possible to change the suffix, compile the file using the -ObjC<\/strong> compiler flag.
\n\ub2f9\uc2e0\uc758 \ud504\ub85c\uc81d\ud2b8\uc911 “.c” \ud30c\uc77c\uc5d0 \ub4e4\uc5b4\uc788\ub294 Objective C\ucf54\ub4dc\uac00 \uc788\ub2e4\uba74, compile\ud560\ub54c file\uacfc \ud568\uaed8 Objective C option\uc774 \ud544\uc694\ud558\uac8c \ub420\uac81\ub2c8\ub2e4. \uac04\ub2e8\ud55c \ubc29\ubc95\uc744 \uc4f0\uc790\uba74 “.c” \ud30c\uc77c\uc758 \ud655\uc7a5\uc790\ub97c “.m”\uc73c\ub85c \ubc14\uafb8\uace0 Interface Builder\uc758 Project Inspector\uc5d0 “.m”\uc73c\ub85c \ubc14\uafbc \ud30c\uc77c\uc774\ub984\uc744 \ucd94\uac00\ud569\ub2c8\ub2e4. \ud655\uc7a5\uc790\ub97c \uc808\ub300 \ubc14\uafc0 \uc218 \uc5c6\ub2e4\uba74 file\uc744 compile\ud560\ub54c -Objc \ucef4\ud30c\uc77c\ub7ec \ud50c\ub798\uadf8\ub97c \uc0ac\uc6a9\ud558\uc2dc\uba74 \ub429\ub2c8\ub2e4.<\/span><\/p>\n

You can place any C code in a “.m” file without any special handling. \u00a0The C code needs to extern id’s as per regular C scoping rules.
\n\ub2f9\uc2e0\uc740 “.m”\ud30c\uc77c\uc5d0 \ubcc4\ub3c4\uc758 \uc5b4\ub5a4 \ud2b9\ubcc4\ud55c \uc870\uc791\ub3c4 \ud558\uc9c0\uc54a\uc740 \uc5b4\ub5a4 C\ucf54\ub4dc\ub3c4 \ub123\uc744 \uc218 \uc788\uc2b5\ub2c8\ub2e4. C\ucf54\ub4dc\ub294 \uc815\uaddc C Scoping \uaddc\uce59\uc5d0 \ub530\ub978 extern id\ub97c \ud544\uc694\ub85c \ud569\ub2c8\ub2e4.<\/span><\/p>\n

Only within Objective-C methods can you directly access instance variables and the hidden variable “self.” \u00a0You must pass an object to a C function that needs access to it. \u00a0 For example, this C function returns the width of a View:
\n\ub2f9\uc2e0\uc740 \uc624\uc9c1 Objective-C \uc758\uba54\uc18c\ub4dc\ub97c \ud1b5\ud574\uc11c\ub9cc \uc778\uc2a4\ud134\uc2a4 \ubcc0\uc218\uc640 \uc228\uaca8\uc9c4 “self”\ubcc0\uc218\uc5d0 \uc9c1\uc811 \uc5d1\uc138\uc2a4 \ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/span>
\n\ub2f9\uc2e0\uc740 \ubc18\ub4dc\uc2dc \uc811\uadfc\ud558\ub824\ub294 \uac1d\uccb4\uc5d0 \u00a0\uc694\uad6c\uac00 \uc788\ub294\u00a0 C \ud568\uc218\uc5d0\uac8c \uc624\ube0c\uc81d\ud2b8\ub97c \ub118\uaca8\uc57c\ud569\ub2c8\ub2e4(\uc778\uc218\ud615\ud0dc\ub85c). \uc608\ub97c \ub4e4\uc790\uba74 \uc774 C\ud568\uc218\ub294 View\uc758 \ub108\ube44\ub97c \ubc18\ud658\ud569\ub2c8\ub2e4.<\/span><\/p>\n

NXCoord widthOfView(View *self) {\u00a0 \u00a0 NXRect b;\u00a0 \u00a0 [self getBounds:&b];\u00a0 \u00a0return b.size.width; }<\/p>\n

You may access public instance variables like this:
\n\ub2f9\uc2e0\uc774 public \uc778\uc2a4\ud134\uc2a4 \ubcc0\uc218\uc5d0 \uc811\uadfc\ud558\ub824\uba74 \uc774\ub807\uac8c \ud574\ub3c4 \ub429\ub2c8\ub2e4.:<\/span><\/p>\n

void setNumber(MyObject *self,int newValue) { \u00a0 \u00a0self->number = newValue; }<\/p>\n

Remember that all instance variables are considered private unless explicitly declared public. \u00a0However, within the confines of a class implementation, all instance variables of that class are considered public. \u00a0So in the implementation for MyControl (a subclass of Control), you could write a C function to set the tag of a MyControl object like this:
\n\uae30\uc5b5\ud558\uc138\uc694. \ubaa8\ub4e0 \uc778\uc2a4\ud134\uc2a4 \ubcc0\uc218\ub294 \uba85\uc2dc\uc801\uc73c\ub85c public\uc73c\ub85c \uc120\uc5b8\ub418\uc9c0 \uc54a\ub294\uacbd\uc6b0 private\uc774\ub77c\ub294\uac78 \uc0dd\uac01\ud574\uc57c \ud569\ub2c8\ub2e4. \uadf8\ub7ec\ub098 Class \uad6c\ud604\uc758 \uacbd\uacc4\uc548\uc5d0\uc11c, \ud074\ub798\uc2a4\uc548\uc758 \ubaa8\ub4e0 \uc778\uc2a4\ud134\uc2a4 \ubcc0\uc218\ub294 public\uc774\ub77c\ub294\uac83\ub3c4 \uc0dd\uac01\ud574\uc57c \ud569\ub2c8\ub2e4. (Control\uc758 \uc11c\ube0c\ud074\ub798\uc2a4\uc778)\u00a0MyControl\uc758 \uad6c\ud604\uc5d0\uc11c, \ub2f9\uc2e0\uc740\u00a0MyControl\uac1d\uccb4\uc758 \ud0dc\uadf8\ub97c \uc124\uc815\ud558\ub294 C\ud568\uc218\ub97c \uc791\uc131\ud560 \uc218 \uc788\uc5c8\uc2b5\ub2c8\ub2e4.<\/span><\/p>\n

void setTag(MyControl *self,int newTag) { \u00a0self->tag = newTag; }<\/p>\n

QA27<\/p>\n

Valid for 1.0, 2.0, 3.0<\/p>\n

 <\/p>\n

jachin, neogeo\ub2d8\uc758 \ub3c4\uc6c0\uc73c\ub85c \ubc88\uc5ed\ub418\uc5c8\uc2b5\ub2c8\ub2e4<\/p>\n","protected":false},"excerpt":{"rendered":"

Q: \u00a0How does one mix C and Objective-C code? \u00a0How can one call Objective-C from C? \uc5b4\ub5bb\uac8c\ud558\uba74 Objective \ucf54\ub4dc\uc640 C\ub97c \uac19\uc774 \uc4f8 \uc218 \uc788\ub098\uc694? \uc5b4\ub5bb\uac8c C\uc5d0\uc11c Objective C\ub97c\u00a0\ud638\ucd9c\ud560 \uc218 \uc788\ub098\uc694?\u00a0 A: \u00a0Just do it! \u00a0C functions can freely send Objective-C messages, and Objective-C methods can freely call C functions. \u00a0 For an example, look at […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24],"tags":[],"_links":{"self":[{"href":"http:\/\/nextstep.onionmixer.net\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/80"}],"collection":[{"href":"http:\/\/nextstep.onionmixer.net\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/nextstep.onionmixer.net\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/nextstep.onionmixer.net\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/nextstep.onionmixer.net\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=80"}],"version-history":[{"count":10,"href":"http:\/\/nextstep.onionmixer.net\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/80\/revisions"}],"predecessor-version":[{"id":118,"href":"http:\/\/nextstep.onionmixer.net\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/80\/revisions\/118"}],"wp:attachment":[{"href":"http:\/\/nextstep.onionmixer.net\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=80"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/nextstep.onionmixer.net\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=80"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/nextstep.onionmixer.net\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=80"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}