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Undefined Reference To Gcc Error

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How to apply for UK visit visa after four refusal How to fix a bent lens mount hook? So I added -lavutil at the end of the command and it compiled. –jamie_y Mar 15 '14 at 17:54 1 This paragraph "Please also note that libraries need to be Is it dangerous to use default router admin passwords if only trusted users are allowed on the network? And linkers do not necessarily have access to the source code for the object files they are linking. weblink

For example, in this C code: int imported(int); static int internal(int x) { return x * 2; } int exported(int x) { return imported(x) * internal(x); } The names of the I am trying to create a shared object (.so) that exports one function, "external()". How to draw a clock-diagram? Modify functions in R using body, formals and environment methods How can I make two cutting lines close to each other?

Gcc Undefined Reference To Function

These aren't "undeclared", they're "undefined". imported is an undefined symbol; in other words, the linker is expected to find it elsewhere. Some of the methods are from libavcodec and the others are from libavutil. Presumably, linkers could just re-scan the whole library list until no new symbols got resolved.

These Aren't Roasted! Return something else? Why was Susan treated so unkindly? Undefined Reference To Gcc Linker Error Why does Wikipedia list an improper pronunciation of Esperanto?

Just a bunch of object files glued together. Undefined Reference To In C For details and our forum data attribution, retention and privacy policy, see here UbuntuCommunityAsk!DeveloperDesignDiscourseHardwareInsightsJujuShopMore ›AppsHelpForumLaunchpadMAASCanonical current community chat Ask Ubuntu Ask Ubuntu Meta your communities Sign up or log in to But wait, there are exceptions!  We know that there are two possibilities for linking, static linking and dynamic linking. http://stackoverflow.com/questions/15141122/how-to-solve-undefined-reference-to-function-error As I wrote, I really would appreciate any help.

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 Undefined Reference To Error Compatible toolchains (like clang instead of gcc) apply too. The only time where a linker goes back to rescan objects it has already seen happens within a single library - as mentioned above, once an object from some library is For all but the very simplest programs, the program is composed of multiple C++ source files (also known as “translation units”).

Undefined Reference To In C

Partial sum of the harmonic series between two consecutive fibonacci numbers Given a limit with notation f, how would you solve? http://askubuntu.com/questions/194193/why-do-i-get-undefined-reference-errors-when-linking-against-openssl Linker 101 To understand the linker, you have to understand how C++ programs are built. Gcc Undefined Reference To Function Let's start with the most basic case, of linking two objects together: $ cat simplefunc.c int func(int i) { return i + 21; } $ cat simplemain.c int func(int); int main(int Undefined Reference To G++ Note: -Wl,--no-as-needed isn't applied globally to everything that's linked, it's only applied to things that follow it in the command line order.

Join 59 other followers Create a free website or blog at WordPress.com. %d bloggers like this: Toggle navigation Eli Bendersky's website About Code Archives Library order in static linking July 09, http://centralpedia.com/undefined-reference/undefined-reference-to-error-in-gcc.html But it makes one wonder - what happens if AA needs a symbol from BB, but BB also needs a symbol from AA? Origin of “can” in the sense of ‘jail’ 2011 MacBook Pro upgrade? Traditionally, linker technology has lagged behind compilers, mostly because it’s generally more fun to build a compiler than to build a linker. Undefined Reference 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. share|improve this answer edited Mar 15 '14 at 18:01 answered Mar 15 '14 at 16:36 alk 45.2k53497 1 And probably something like -L$HOME/ffmpeg/lib in this case, since ffmpeg is in asked 4 years ago viewed 15989 times active 4 years ago Linked 0 compile C in CentOS face error: undefined reference to 11 Why does the library linker flag sometimes have check over here 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

Suppose we have this code: volatile char src[] = {1, 2, 3, 4, 5}; volatile char dst[50] = {0}; void* memcpy(void* dst, void* src, int len); int main(int argc, const char* Gcc Undefined Reference To Sqrt Development of retrosynthesis plan In order to become a pilot, should an individual have an above average mathematical ability? Ask Ubuntu works best with JavaScript enabled current community chat Unix & Linux Unix & Linux Meta your communities Sign up or log in to customize your list.

share|improve this answer edited Sep 28 '12 at 22:12 answered Sep 28 '12 at 21:34 izx 92.1k22216261 add a comment| Your Answer draft saved draft discarded Sign up or log

Anyhow, as you can see the object files and libraries are provided in a certain order on the command-line, from left to right. share|improve this answer edited Nov 15 '11 at 17:56 answered Nov 15 '11 at 17:34 Flexo♦ 55k16103167 1 Thanks for also adding "--as-needed/--no-as-needed" explanation. But when I try to compile the file that I really want to use "vclient.c" I get an error message /tmp/ccuuPxtN.o(.text+0x3bc): In function `main': vclient.c: undefined reference to `initLog' Now as Gcc Undefined Reference To Static Library What undefined symbols does the symbol table contain when the linker first sees -lfunc_dep?

simplemain.o -lbar_dep -lfunc_dep ./libfunc_dep.a(func_dep.o): In function 'func': func_dep.c:(.text+0x14): undefined reference to 'bar' collect2: ld returned 1 exit status To solve this, consider that it's perfectly valid to list a library more Does Nietzsche's rejection of Socrates mean that he is a relativist about ethics? There's at least one another linker flag that can help us resolve the circular dependency here. this content Don't show this message again Change Settings Privacy Policy Update ARM’s Privacy Policy has been updated.