Home > Undefined Reference > Linking Error Undefined Reference To Function

Linking Error Undefined Reference To Function


Can cats leave scratch marks on cars? You can see that -lcfitsio -lm comes from line 301 in the makefile, how can I set it so that it comes at the end of the gcc commands? When the linker tries to create the entire program, it then complains that the implementation (toHash::insert(int, char)) cannot be found. Tango Icons Tango Desktop Project. this contact form

Are leet passwords easily crackable? Attempting to link a C++ object file with the C compiler gcc will cause "undefined reference" errors for C++ standard library functions: $ g++ -Wall -c hello.cc $ gcc hello.o (should This brings us to the most important corollary of the linking process outlined above: If object or library AA needs a symbol from library BB, then AA should come before library When I look in common.h I find int initLog(int useSyslog, char *logfile,int debugSwitch); and looking in common.c (also in the same directory) I find int initLog(int useSyslog, char *logfile,int debugSwitch) { additional hints

Linking Error Undefined Reference To Function

In the end I just entered that gcc command manually and used make again to finish it off. –relo Jul 20 '15 at 17:47 add a comment| Your Answer draft When to use "bon appetit"? Is the NHS wrong about passwords? By convention the names of library files are prefixed with lib and (in their static form) have a .a extension.

share|improve this answer answered Sep 27 '08 at 12:33 Remo.D 12k33257 add a comment| up vote 1 down vote Post your makefile, and the library function you are trying to call. share|improve this answer edited Nov 4 '15 at 20:39 Paul Pettengill 2,97911928 answered Jan 28 '13 at 8:04 Saqlain 8,72831527 add a comment| Not the answer you're looking for? For example: /* myapp.h ** Here I will include and define my stuff */ ... #include "mylib.h" ... Undefined Reference To C With the passing of Thai King Bhumibol, are there any customs/etiquette as a traveler I should be aware of?

how can you tell if the engine is not brand new? Why is absolute zero unattainable? Thus, you will change the command to: gcc -g -O2 -fopenmp -L/usr/lib -o lenstool_tab e_nfwg.o lenstool_tab.o midpnt.o nrutil.o polint.o qromo.o read_bin.o lenstool_tab.o -lcfitsio -lm This should fix your problem. Read More Here We can use the --undefined flag to tell the linker - "buddy, here's a symbol I want you to add to the undefined list".

Make sure -lstdc++ is at the end of the command. Undefined Reference C++ If you haven't defined Hash class member functions, you need to do that first, then compile Hash.cpp and main.cpp then link them properly. These Aren't Roasted! Return something else?

Undefined Reference To Function C++

This code illustrates the problem: int foo(); int main() { foo(); } Here, we have a declaration of the function foo(), which we call in main(), but no definition. http://askubuntu.com/questions/194193/why-do-i-get-undefined-reference-errors-when-linking-against-openssl The basics Let's start by defining the scope of this article: first, my examples are demonstrating the use of the gcc and binutils toolchain on Linux. Linking Error Undefined Reference To Function imported is an undefined symbol; in other words, the linker is expected to find it elsewhere. Linker Error Undefined Reference To When the linker finishes, it looks at the symbol table.

internal is defined within the object but invisible from the outside. weblink When the linker does reach simplemain.o and sees that func is, indeed required, it's added to the undefined list (because it's not on the exported list). Would you expect it to still return 5? Is it plausible for my creature to have similar IQ as humans? Gcc Undefined Reference To Function

Let's compile it and look at the symbol table: $ gcc -c x.c $ nm x.o 000000000000000e T exported U imported 0000000000000000 t internal This means: exported is an external symbol Also note that when a library is examined, an object file within it can be left out of the link if it does not provide symbols that the symbol table needs. For example, when you create an executable and forget to include the file with the main function, you'll get something like: /usr/lib/x86_64-linux-gnu/crt1.o: In function '_start': (.text+0x20): undefined reference to 'main' collect2: http://xhpcreations.com/undefined-reference/gcc-undefined-reference-to-function.html Why must the speed of light be the universal speed limit for all the fundamental forces of nature?

Thank you Neill I am a newbie. G++ Undefined Reference To Why not? The linking process This section defines the linking process in a somewhat dry, algorithmic manner.

With the passing of Thai King Bhumibol, are there any customs/etiquette as a traveler I should be aware of?

Can Communism become a stable economic strategy? Sometimes I feel that I understand things, turn the corner and find that there is even more to understand. What happens if one brings more than 10,000 USD with them in the US? Ld Undefined Reference To Function How to handle a senior developer diva who seems unaware that his skills are obsolete?

Conclusion The algorithm used by the linker to resolve symbols between objects and libraries is pretty simple. Adv Reply February 14th, 2011 #2 Arndt View Profile View Forum Posts Private Message Ubuntu Cappuccino Scuro Join Date May 2006 Beans 1,787 Re: compiling with gcc and "undefined reference If you still run into problematic situations you're not sure how to resolve, this article mentioned two tools that can be very useful in debugging such problems: one is nm, which http://xhpcreations.com/undefined-reference/undefined-reference-to-function-c-programming.html To allow the linker find the function's implementation (and get rid of the undefined reference) you need to ask the compiler driver (gcc) to link the specific library where the function

Note that since these are object files, the linking order does not matter. If those answers do not fully address your question, please ask a new question. 1 That's not a compiler error. –chris Jan 28 '13 at 7:56 1 -1 for How exactly does the typical shell "fork bomb" calls itself twice? Why microcontroller takes many clock cycles to start up with PLL clock source?

more stack exchange communities company blog Stack Exchange Inbox Reputation and Badges sign up log in tour help Tour Start here for a quick overview of the site Help Center Detailed But note what happens if the linking order is reversed now: $ gcc -L. -lsimplefunc simplemain.o simplemain.o: In function 'main': simplemain.c:(.text+0x15): undefined reference to 'func' collect2: ld returned 1 exit status Here's how this helps in our case: $ gcc simplemain.o -L. -Wl,--start-group -lbar_dep -lfunc_dep -Wl,--end-group $ ./a.out ; echo $? 24 It's interesting to note the "significant performance cost" warning in I am a newbie.

Let's say you have a library libmylib.a that contains the function myfunc() and a corresponding header mylib.h that defines its prototype. It's better to make it as fast as possible for well-behaved programs (that got their linking order right), and provide special options like groups for the difficult circular dependency cases.