c - use extern structure variable defined in a library, config with cmake -

-

main.c

#include "test.h" extern struct test_struct my_test_str; // defined in my_test_lib.a  int main(int argc, char *argv[]) {    return 0; }

here my_test_my library file of test.h , test.c compiled my_test_lib.a

test.h

#ifndef test_my #define test_my struct test_struct {   double d1;   double d2;   double d3; }; void ddd(void); #endif

test.c

struct test_struct my_test_str; void ddd(void) {   int = 0;   int c = 1;   c = + c; }

write cmakelists.txt , use cmake generated makefile

cmake_minimum_required(version 2.6) project(tutorial)  add_library(my_test_my test.c) add_executable(tutorial main.c) target_link_libraries (tutorial my_test_my)

after generate makefiles in out directory, execute make

192:out jerryw$ make [ 25%] building c object cmakefiles/my_test_my.dir/test.c.o [ 50%] linking c static library libmy_test_my.a /applications/xcode.app/contents/developer/toolchains/xcodedefault.xctoolchain/usr/bin/ranlib: file: libmy_test_my.a(test.c.o) has no symbols /applications/xcode.app/contents/developer/toolchains/xcodedefault.xctoolchain/usr/bin/ranlib: file: libmy_test_my.a(test.c.o) has no symbols warning: /applications/xcode.app/contents/developer/toolchains/xcodedefault.xctoolchain/usr/bin/ranlib: warning library: libmy_test_my.a table of contents empty (no object file members in library define global symbols) [ 50%] built target my_test_my [ 75%] building c object cmakefiles/tutorial.dir/main.c.o [100%] linking c executable tutorial undefined symbols architecture x86_64:   "_ddd", referenced from:       _main in main.c.o   "_my_test_str", referenced from:       _main in main.c.o ld: symbol(s) not found architecture x86_64 clang: error: linker command failed exit code 1 (use -v see invocation) make[2]: *** [tutorial] error 1 make[1]: *** [cmakefiles/tutorial.dir/all] error 2 make: *** [all] error 2

why happened ?


Comments

Post a Comment

Popular posts from this blog

mysql - Dreamhost PyCharm Django Python 3 Launching a Site -

-
i'm new python/django , created simple django website using pycharm. site works fine running on computer, i'm lost when comes taking site onto host (dreamhost). i'm able upload files correct directories fine, , believe made correct changes database on mysql. i'm not sure go there though. right now, page shows files rather site. direction appreciated. much! you should not run django application using python manage.py runserver on production. how run application on django depends on server (apache, nginx) want use for apache - https://docs.djangoproject.com/en/1.10/howto/deployment/wsgi/modwsgi/ for nginx - https://www.digitalocean.com/community/tutorials/how-to-serve-django-applications-with-uwsgi-and-nginx-on-ubuntu-14-04 the mysql database should, of course, exist , have correct credentials. or, if choose use sqlite, file should accessible, readable , writable www-user (may different depending on linux distributive)
Read more

java - Sending SMS with SMSLib and Web Services -

-
i have made rest web service send smss using hsdpa usb modem. using smslib in java send smss. every time web service invoked, create gateway start service, send message, stop service , remove gateway. takes 20 seconds each message. found starting service takes lot of time. part of code use send smss service.getinstance().addgateway(gateway); service.getinstance().startservice(); outboundmessage msg = new outboundmessage(phonenumber, message); if (service.getinstance().sendmessage(msg)) { result = "message sent successfully!!"; } else { result = "could not send message."; } service.getinstance().stopservice(); service.getinstance().removegateway(gateway);//remove gateway is there way can start service once if not started , use send message when ever web service invoked? why dont group messages , send in 1 go? service.getinstance().sendmessages(messa...
Read more

java - How to resolve The method toString() in the type Object is not applicable for the arguments (InputStream) -

-
i'm trying read json file local machine. @path("/") public class jsonparsing { file f = new file("file.json"); if (f.exists()){ inputstream = new fileinputstream("file.json"); string jsontxt = ioutils.tostring(is); system.out.println(jsontxt); jsonobject json = new jsonobject(jsontxt); string = json.getstring("1000"); system.out.println(a); } } but i'm getting error in tostring() method. possible read .txt file containing json object local machine? if possible, how done? firstly: whenever ask question- add imports well. secondly: yes possible read .txt file containing json object. steps: 1. add maven dependency in pom.xml - <dependency> <groupid>com.googlecode.json-simple</groupid> <artifactid>json-simple</artifactid> <version>1.1.1</version> </dependency> or add jar of dependency. 2.import...
Read more