I have already taken a look at the question :Undefined reference to `pow' and `floor' but I'd like to know if there is anyway I could fix this permanently in my IDE which is Jet brains C Lion. I am using it on Pop OS. And I am very new to C as well as programming in general, it'd be better if I could just build and compile the program from my IDE rather than having to go to terminal every time.
Edit #1 : This is the code I am trying to compile rn. Its trying to find the reverse of a number rn.
#include <stdio.h>
#include <math.h>
int how_long(int x)
{
int count = 0;
while (x>0)
{
x /= 10;
count++;
}
return count;
}
int main()
{
int n = 1;
int num ;
int reverse_num = 0;
printf("Enter a number : ");
scanf("%i",&num);
int j = how_long(num);
while (num>0)
{
reverse_num += (num % 10) * (int)pow(10,j) ;
num -= (num%10) * (int)pow(10,n-1);
++n;
--j;
}
printf("%i",reverse_num);
return 0;
}
And the error I get on C Lion is :
[1/1] Linking C executable 5_2
FAILED: 5_2
: && /usr/bin/cc -g CMakeFiles/5_2.dir/main.c.o -o 5_2 && :
/usr/bin/ld: CMakeFiles/5_2.dir/main.c.o: in function `main':
/home/koustubhjain/CLionProjects/Assignments/5-2/main.c:30: undefined reference to `pow'
/usr/bin/ld: /home/koustubhjain/CLionProjects/Assignments/5-2/main.c:31: undefined reference to `pow'
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.
Edit #2 :
I found this old forum post on C Lion's website : https://intellij-support.jetbrains.com/hc/en-us/community/posts/206607085-CLion-Enabling-math-h-for-C-projects
but idk if it still works, and if it works, how do I add that to my CMake file ?
Here is my CMakeLists.txt file for reference :
cmake_minimum_required(VERSION 3.21)
project(5_2 C)
set(CMAKE_C_STANDARD 99)
add_executable(5_2 main.c)
Edit #3 : Edit #2 seems to have fixed it
Related
#include <stdio.h>
#include <math.h>
int exp_for_level(int n) {
return (int)(100 * pow(n, 2.3));
}
int main(){
int x;
x = exp_for_level(6);
printf("%d", x);
return 0;
}
I receive the following error when I run this code on an online compiler
/tmp/cc28S7ML.o: In function exp_for_level':
main.c:(.text+0x19): undefined reference to `pow'
collect2: error: ld returned 1 exit status
How do I rectify this?
After I couldn't get it to work on the online compiler, I followed advice from some other threads on
The file is stored under a file grades.c on my mac
I've tried entering this
$ gcc - Wall - lm -o grades grade . c
into my terminal and i just get zsh error: command not found
Any ideas on what the issue is here too?
The online compiler I'm using is
https://www.tutorialspoint.com/compile_c_online.php
EDIT: in my post, in main I'd miswritten the function as exp_to_level instead of exp_for_level. Didn't copy paste the entire code as it's too long. I narrowed it down and retyped it to the portion that yields the error.
There are some errors in your code, you have defined a function exp_for_level but you use exp_to_level.
Then your x variable is not defined
If you fix your code like this:
#include <stdio.h>
#include <math.h>
int exp_for_level(int n) {
return (int)(100 * pow(n, 2.3));
}
int main(){
int x = exp_for_level(6);
printf("%d", x);
return 0;
}
and you compile:
gcc -Wall powtest.c -o powtest -lm
it works.
About the error on the online compiler:
The undefined reference error occurs because you are missing -lm linker option.
Edit the online compiler command clicking on Project->Compile Options:
About this problem on your local machine:
After I couldn't get it to work on the online compiler, I followed
advice from some other threads on The file is stored under a file
grades.c on my mac I've tried entering this
$ gcc - Wall - lm -o grades grade . c
into my terminal and i just get zsh error: command not found
you don't have the compiler installed.
You should install clang, Have a look to this question
First of all your function name is wrong in the main take a look here exp_for_level
and in main its exp_to_level change one of them then also add int x in main to solve the issue.
This question already has answers here:
undefined symbol for architecture x86_64 in compiling C program [duplicate]
(1 answer)
What is an undefined reference/unresolved external symbol error and how do I fix it?
(39 answers)
Closed 3 years ago.
Why does main.c fail to compile when including sum_divisibles.h?
I am sure I am missing something silly, but can't find it for the life of me.
Compiling on Mac OSX.
sum_divisibles.h
#ifndef SUM_DIVISIBLES
#define SUM_DIVISIBLES
int sum_divisibles(int limit);
#endif /* SUM_DIVISIBLES */
sum_divisibles.c
#include <stdlib.h>
#include "sum_divisibles.h"
int sum_divisibles(int limit)
/* Returns sum of multiples of 3 and 5 less than limit. */
{
int mult_3, mult_5, sum = 0;
for (int ndx=0; (mult_3 = ndx * 3 ) < limit; ndx++) {
if ( (mult_5 = ndx * 5) < limit && mult_5 % 3 != 0 ) {
sum += mult_5 ;
}
}
return sum; }
main.c
#include <stdio.h>
#include "sum_divisibles.h" // does not compile
//#include "sum_divisibles.c" // compiles
int main(void)
{
printf("%d\n", sum_divisibles(1000));
}
Error -- on gcc -Wall main.c
Undefined symbols for architecture x86_64:
"_sum_divisibles", referenced from:
_main in main-e4e97
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
This question already has answers here:
gcc will not properly include math.h
(2 answers)
Closed 8 years ago.
I'm trying to learn enough c to satisfy my occasional need to write simple programs that answer specific questions I have. I've been following a tutorial and using Geany for ease of use. Instead, I can't seem to get the simplest program to run. Here is my source code:
#include <stdio.h>
#include <math.h>
int main(int argc, char **argv)
{
int x, y;
double c, sqr_c;
for (x = 10; x <= 31; x++)
{
for (y = 10; y <= 31; y++)
{
c = 1000 * x * x + y * y;
sqr_c = sqrt(c);
printf ("%f\n", sqr_c);
}
}
return 0;
}
It compiles fine (gcc -c) but when I try to build an executable, I get:
gcc "concsqr.c" -Wall -o "concsqr" (in directory: /home/chip)
/tmp/cccSmdZS.o: In function `main':
concsqr.c:(.text+0x4b): undefined reference to `sqrt'
collect2: error: ld returned 1 exit status
Compilation failed.
I read something about making sure the linker can locate the library where sqrt() is defined, but I do not know how to do that, and wouldn't it be in a standard location anyway? Why doesn't the linker already know where it is? It's a standard library for c.
You must try to compile your program with the -lm flag as libm.so is the math library, and the -l flag adds a lib prefix and .a or .so suffix.
gcc concsqr.c -Wall -o concsqr -lm
I'm trying to build a basic FANN (Fast Artificial Neural Network) project on Windows with MinGW. However, whenever I try to link the executable, I run into a bunch of undefined reference to errors. Interestingly, if I don't link the library at all, I get more errors, implying that at least some of the library is working. The code for the file I'm trying to compile and link is:
#include "doublefann.h"
int main() {
const unsigned int num_input_neurons = 9;
const unsigned int num_output_neurons = 1;
const unsigned int num_layers = 3;
const unsigned int num_hidden_neurons = 9;
const float desired_error = (const float) 0;
const unsigned int max_epochs = 500000;
const unsigned int epochs_between_reports = 1000;
struct fann *ann = fann_create_standard(num_layers,
num_input_neurons,
num_hidden_neurons,
num_output_neurons);
fann_set_activation_function_hidden(ann, FANN_SIGMOID_SYMMETRIC);
fann_set_activation_function_output(ann, FANN_SIGMOID_SYMMETRIC);
fann_train_on_file(ann,
"titanic-training.data",
max_epochs,
epochs_between_reports,
desired_error);
fann_save(ann, "titanic.net");
fann_destroy(ann);
return 0;
}
and the command I'm using to compile and link is:
gcc -Wall -Ifann\src\include titanic-train.c -Lfann\bin -lfanndouble -o titanic-train.exe
The errors I'm getting back are:
C:\Users\kunkelwe\AppData\Local\Temp\ccsWQg66.o:titanic-train.c:(.text+0x7f): undefined reference to `fann_set_activation_function_hidden'
C:\Users\kunkelwe\AppData\Local\Temp\ccsWQg66.o:titanic-train.c:(.text+0x93): undefined reference to `fann_set_activation_function_output'
C:\Users\kunkelwe\AppData\Local\Temp\ccsWQg66.o:titanic-train.c:(.text+0xbf): undefined reference to `fann_train_on_file'
C:\Users\kunkelwe\AppData\Local\Temp\ccsWQg66.o:titanic-train.c:(.text+0xd3): undefined reference to `fann_save'
C:\Users\kunkelwe\AppData\Local\Temp\ccsWQg66.o:titanic-train.c:(.text+0xdf): undefined reference to `fann_destroy'
c:/fragileprograms/mingw-native/bin/../lib/gcc/mingw32/4.8.1/../../../../mingw32/bin/ld.exe: C:\Users\kunkelwe\AppData\Local\Temp\ccsWQg66.o: bad reloc address 0x64 in section `.rdata'
c:/fragileprograms/mingw-native/bin/../lib/gcc/mingw32/4.8.1/../../../../mingw32/bin/ld.exe: final link failed: Invalid operation
collect2.exe: error: ld returned 1 exit status
If I don't link the library at all, I instead get:
C:\Users\kunkelwe\AppData\Local\Temp\ccyOO3jL.o:titanic-train.c:(.text+0x67): undefined reference to `fann_create_standard'
C:\Users\kunkelwe\AppData\Local\Temp\ccsWQg66.o:titanic-train.c:(.text+0x7f): undefined reference to `fann_set_activation_function_hidden'
C:\Users\kunkelwe\AppData\Local\Temp\ccsWQg66.o:titanic-train.c:(.text+0x93): undefined reference to `fann_set_activation_function_output'
C:\Users\kunkelwe\AppData\Local\Temp\ccsWQg66.o:titanic-train.c:(.text+0xbf): undefined reference to `fann_train_on_file'
C:\Users\kunkelwe\AppData\Local\Temp\ccsWQg66.o:titanic-train.c:(.text+0xd3): undefined reference to `fann_save'
C:\Users\kunkelwe\AppData\Local\Temp\ccsWQg66.o:titanic-train.c:(.text+0xdf): undefined reference to `fann_destroy'
c:/fragileprograms/mingw-native/bin/../lib/gcc/mingw32/4.8.1/../../../../mingw32/bin/ld.exe: C:\Users\kunkelwe\AppData\Local\Temp\ccsWQg66.o: bad reloc address 0x64 in section `.rdata'
c:/fragileprograms/mingw-native/bin/../lib/gcc/mingw32/4.8.1/../../../../mingw32/bin/ld.exe: final link failed: Invalid operation
collect2.exe: error: ld returned 1 exit status
Edit:
As per Haroogan's request, I ran nm fanndouble.lib. The output is rather extensive, so rather than paste it all here, I've made it available via pastebin here: http://pastebin.com/raw.php?i=vybFhEcX
I'm not familiar with nm, but it appears that the missing symbols do exist in the file.
Edit #2:
The contents of doublefann.h are: http://pastebin.com/mrHKJi8C
and the contents of fann.h, which it includes are: http://pastebin.com/gTrHCYAg
Could the problem just be solved by recompiling the library with MinGW?
Edit #3:
Making the changes that Haroogan suggested worked! In addition to those changes, I had to modify the CMakeLists.txt file for FANN by adding:
if (WIN32)
ADD_DEFINITIONS(-DFANN_DLL_EXPORTS)
endif (WIN32)
Then, running cmake -G "MinGW Makefiles" and then mingw32-make in the root of the project produced a file, libdoublefann.dll, that when linked against and included in the directory of the .exe, allowed me, finally, to run my program.
In doublefann.h on the line #116:
#if (_MSC_VER > 1300)
change to:
#if (_MSC_VER > 1300) || defined(__MINGW32__) || defined(__MINGW64__)
Furthermore, on the line #121:
#if defined(_MSC_VER) && (defined(FANN_USE_DLL) || defined(FANN_DLL_EXPORTS))
change to:
#if (defined(_MSC_VER) || defined(__MINGW32__) || defined(__MINGW64__)) && \
(defined(FANN_USE_DLL) || defined(FANN_DLL_EXPORTS))
I am trying to write a program to approximate pi. It basically takes random points between 0.00 and 1.00 and compares them to the bound of a circle, and the ratio of points inside the circle to total points should approach pi (A very quick explanation, the specification goes in depth much more).
However, I am getting the following error when compiling with gcc:
Undefined first referenced
symbol in file
pow /var/tmp//cc6gSbfE.o
ld: fatal: symbol referencing errors. No output written to a.out
collect2: ld returned 1 exit status
What is happening with this? I've never seen this error before, and I don't know why it's coming up. Here is my code (though I haven't fully tested it since I can't get past the error):
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
int main(void) {
float x, y;
float coordSquared;
float coordRoot;
float ratio;
int n;
int count;
int i;
printf("Enter number of points: ");
scanf("%d", &n);
srand(time(0));
for (i = 0; i < n; i++) {
x = rand();
y = rand();
coordSquared = pow(x, 2) + pow(y, 2);
coordRoot = pow(coordSquared, 0.5);
if ((x < coordRoot) && (y < coordRoot)) {
count++;
}
}
ratio = count / n;
ratio = ratio * 4;
printf("Pi is approximately %f", ratio);
return 0;
}
use -lm during compilation(or linking) to include math library.
Like this: gcc yourFile.c -o yourfile -lm
need to Link with -lm.
gcc test.c -o test -lm
The error is produced by the linker, ld. It is telling you that the symbol pow cannot be found (is undefined in all the object files handled by the linker). The solution is to include the library which includes the implementation of the pow() function, libm (m for math). [1] Add the -lm switch to your compiler command line invocation (after all the source file specifications) to do so, e.g.
gcc -o a.out source.c -lm
[1] Alternatively, you could have your own implementation of pow() in a separate translation unit or a library, but you would still have to tell the compiler/linker where to find it.