Gcc Error Undefined Reference Sqrt
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn more about undefined reference to sqrt collect2 ld returned 1 exit status hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask
Undefined Reference To Sqrt Ubuntu
Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other.
Undefined Reference To Sqrt' Eclipse
Join them; it only takes a minute: Sign up Why am I getting “undefined reference to sqrt” error even though I include math.h header? up vote 34 down vote favorite 12 I'm very new to C and I have
Undefined Reference To Sqrt Makefile
this code: #include #include int main(void) { double x = 0.5; double result = sqrt(x); printf("The square root of %lf is %lf\n", x, result); return 0; } But when I compile this with: gcc test.c -o test I get an error like this: /tmp/cc58XvyX.o: In function `main': test.c:(.text+0x2f): undefined reference to `sqrt' collect2: ld returned 1 exit status Why does this happen? Is sqrt() not in the math.h header file? I get the same error with how to include math.h in gcc cosh and other trigonometric functions. Why? c linker libm share|improve this question edited Dec 13 '14 at 17:11 Jonathan Leffler 439k62511823 asked May 2 '12 at 6:53 Ant's 4,964863116 And here is some speculation why about why libm isn't linked by default even though it contains part of the standard library: stackoverflow.com/questions/1033898/… –Michael Burr May 2 '12 at 7:01 It's a duplicate to this one: stackoverflow.com/q/5248919/694576 –alk May 2 '12 at 7:10 add a comment| 4 Answers 4 active oldest votes up vote 54 down vote accepted The math library must be linked in when building the executable. How to do this varies by environment, but in Linux/Unix, just add -lm to the command: gcc test.c -o test -lm The math library is named libm.so, and the -l command option assumes a lib prefix and .a or .so suffix. share|improve this answer edited May 2 '12 at 8:12 answered May 2 '12 at 6:55 wallyk 42.1k94899 add a comment| up vote 5 down vote You need to link the with the -lm linker option You need to compile as gcc test.c -o test -lm gcc (Not g++) historically would not by default include the mathematical functions while linking. It has also been separated from libc onto a separate library libm. To link with these functions you have to advise the linker to include the library -l linker option
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of bash: ./a.out: no such file or directory this site About Us Learn more about Stack Overflow the company Business sqrt in c without using sqrt function Learn more about hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask undefined reference to `sqrtf' Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up http://stackoverflow.com/questions/10409032/why-am-i-getting-undefined-reference-to-sqrt-error-even-though-i-include-math C - undefined reference to sqrt (or other mathematical functions) up vote 30 down vote favorite 8 I have this simple code: max = (int) sqrt (number); and in the header I have: #include But application still says undefined reference to sqrt. Do you see any problem here? It looks like everything should be okay. c share|improve this question edited Feb 27 http://stackoverflow.com/questions/5248919/c-undefined-reference-to-sqrt-or-other-mathematical-functions '14 at 23:51 Jonathan Leffler 439k62511823 asked Mar 9 '11 at 16:32 Waypoint 4,4592681152 4 What do you mean by "#import"? You need #include . –hennes Mar 9 '11 at 16:34 Do you mean #include? –Nick Mar 9 '11 at 16:34 Which complains, the linker or the compiler? If you can post the exact error that'd probably clear things up. –Tommy Mar 9 '11 at 16:36 compiler write this complain, problem is, that app don't even built... –Waypoint Mar 9 '11 at 16:40 4 The problem is not in your program but in your system's implementation of the C library. It's still following 1970s/1980s legacy conventions where the math functions are in a separate library and not linked by default. –R.. Mar 9 '11 at 18:52 add a comment| 2 Answers 2 active oldest votes up vote 52 down vote accepted You may find that you have to link with the math libraries on whatever system you're using, something like: gcc -o myprog myprog.c -L/path/to/libs -lm ^^^ - this bit here. Including headers lets a compiler know about func
Get Kubuntu Get Xubuntu Get Lubuntu Get UbuntuStudio Get Mythbuntu Get Edubuntu Get Ubuntu-GNOME Get UbuntuKylin Ubuntu Code of Conduct Ubuntu Wiki Community Wiki Other Support Launchpad Answers Ubuntu IRC Support AskUbuntu Official Documentation User Documentation Social Media Facebook Twitter Useful https://ubuntuforums.org/showthread.php?t=1802431 Links Distrowatch Bugs: Ubuntu PPAs: Ubuntu Web Upd8: Ubuntu OMG! Ubuntu Ubuntu Insights Planet Ubuntu Activity Page Please read before SSO login Advanced Search Forum The Ubuntu Forum Community Ubuntu Specialised Support Development & Programming Programming Talk gcc: undefined https://bytes.com/topic/c/answers/519717-how-use-sqrt-function-gcc reference to `sqrt' even if I included math.h Having an Issue With Posting ? Do you want to help us debug the posting issues ? < is the place to report it, thanks ! Results 1 to 3 of undefined reference 3 Thread: gcc: undefined reference to `sqrt' even if I included math.h Thread Tools Show Printable Version Subscribe to this Thread… Display Linear Mode Switch to Hybrid Mode Switch to Threaded Mode July 12th, 2011 #1 skytreader View Profile View Forum Posts Private Message A Carafe of Ubuntu Join Date Aug 2009 Beans 124 gcc: undefined reference to `sqrt' even if I included math.h So I have this C code: Code: #include #include #include double dist(int x1, int y1, undefined reference to int x2, int y2){ double dx = (double) (x1 - x2); double dy = (double) (y1 - y2); double xx = pow(dx, 2.0); double yy = pow(dy, 2.0); double distance = sqrt(xx + yy); return distance; } But gcc complains that: Code: /tmp/cck84m3o.o: In function `dist': astar.c:(.text+0x5d): undefined reference to `sqrt' collect2: ld returned 1 exit status I don't get why gcc would say that. Anything I missed? Adv Reply July 12th, 2011 #2 JupiterV2 View Profile View Forum Posts Private Message Tea Glorious Tea! Join Date Sep 2006 Location BC, Canada Beans 347 DistroUbuntu 10.10 Maverick Meerkat Re: gcc: undefined reference to `sqrt' even if I included math.h You need to link the math library. Use -lmath or -lm (short-hand) flags. Current Project: Vocab Builder Blog: http://noeffclue.blogspot.com Adv Reply July 12th, 2011 #3 dwhitney67 View Profile View Forum Posts Private Message Tolerant of Ubuntu Join Date Jun 2007 Location Maryland, US Beans 6,272 DistroKubuntu Re: gcc: undefined reference to `sqrt' even if I included math.h Originally Posted by skytreader I don't get why gcc would say that. Anything I missed? That's because math.h is merely a header file with function declarations. It does NOT include the implementation of the functions themselves; those are located elsewhere, namely in libm.so If you read the man-page for sqrt, you will note that it states to link with -lm (as JupiterV2 has already indica
question and get tips & solutions from a community of 418,553 IT Pros & Developers. It's quick & easy. How to use sqrt() function with gcc? P: n/a John I'm trying to use the sqrt() function in Linux with GCC v3.3.6, compiling with this command: $ gcc sourcefile.c I get this error: In function 'main': undefined reference to 'sqrt' collect2: ld returned 1 exit status Here is my source code: #include #include main() { double num, sq_double; scanf("%d", &num); sq_double = sqrt(num); } What am I doing wrong? Is there something special I need to do to use the math.h functions? Aug 4 '06 #1 Post Reply Share this Question 3 Replies P: n/a MrDev Try gcc -lm sourcefile.c John wrote: I'm trying to use the sqrt() function in Linux with GCC v3.3.6, compiling with this command: $ gcc sourcefile.c I get this error: In function 'main': undefined reference to 'sqrt' collect2: ld returned 1 exit status Here is my source code: #include #include main() { double num, sq_double; scanf("%d", &num); sq_double = sqrt(num); } What am I doing wrong? Is there something special I need to do to use the math.h functions? Aug 4 '06 #2 P: n/a Richard Heathfield John said: I get this error: In function 'main': undefined reference to 'sqrt' collect2: ld returned 1 exit status scanf("%d", &num); %lf for double. %d is for ints. sq_double = sqrt(num); } What am I doing wrong? Is there something special I need to do to use the math.h functions? For gcc, yes, you need to tell it to link the math library in, by adding -lm at the end of your gcc call. -- Richard Heathfield "Usenet is a strange place" - dmr 29/7/1999 http://www.cpax.org.uk email: rjh at above domain (but drop the www, obviously) Aug 4 '06 #3 P: n/a Keith Thompson John , question 14.3. -- Keit