link error: undefined reference to 'sqrt' is a link error.
make: Entering directory `/home/richel/Projects/Test/CppLinkErrorUndefinedReferenceToSqrt-build-desktop-Qt_4_8_3_in_PATH__System__Release' gcc -c -x c -O2 -Wall -W -D_REENTRANT -DQT_WEBKIT -DQT_NO_DEBUG -I/usr/share/qt4/mkspecs/linux-g++ -I../CppLinkErrorUndefinedReferenceToSqrt -I/usr/include/qt4 -I/opt/NAG/cll3a09dgl/include -I. -I../CppLinkErrorUndefinedReferenceToSqrt -I. -o main.o ../CppLinkErrorUndefinedReferenceToSqrt/main.cpp g++ -Wl,-O1 -o CppLinkErrorUndefinedReferenceToSqrt main.o -L/usr/lib/i386-linux-gnu -L/opt/NAG/cll3a09dgl/lib -lnagc_nag -lpthread /opt/NAG/cll3a09dgl/lib/libnagc_nag.so: undefined reference to `sqrt' make: Leaving directory `/home/richel/Projects/Test/CppLinkErrorUndefinedReferenceToSqrt-build-desktop-Qt_4_8_3_in_PATH__System__Release' /opt/NAG/cll3a09dgl/lib/libnagc_nag.so: undefined reference to `floor' /opt/NAG/cll3a09dgl/lib/libnagc_nag.so: undefined reference to `ceil' /opt/NAG/cll3a09dgl/lib/libnagc_nag.so: undefined reference to `cosh' /opt/NAG/cll3a09dgl/lib/libnagc_nag.so: undefined reference to `expm1f' /opt/NAG/cll3a09dgl/lib/libnagc_nag.so: undefined reference to `tan' /opt/NAG/cll3a09dgl/lib/libnagc_nag.so: undefined reference to `tanh' /opt/NAG/cll3a09dgl/lib/libnagc_nag.so: undefined reference to `powf' /opt/NAG/cll3a09dgl/lib/libnagc_nag.so: undefined reference to `log' /opt/NAG/cll3a09dgl/lib/libnagc_nag.so: undefined reference to `atan' /opt/NAG/cll3a09dgl/lib/libnagc_nag.so: undefined reference to `expm1' /opt/NAG/cll3a09dgl/lib/libnagc_nag.so: undefined reference to `sinh' /opt/NAG/cll3a09dgl/lib/libnagc_nag.so: undefined reference to `fmod' /opt/NAG/cll3a09dgl/lib/libnagc_nag.so: undefined reference to `exp' /opt/NAG/cll3a09dgl/lib/libnagc_nag.so: undefined reference to `sin' /opt/NAG/cll3a09dgl/lib/libnagc_nag.so: undefined reference to `rint' /opt/NAG/cll3a09dgl/lib/libnagc_nag.so: undefined reference to `pow' /opt/NAG/cll3a09dgl/lib/libnagc_nag.so: undefined reference to `atan2' /opt/NAG/cll3a09dgl/lib/libnagc_nag.so: undefined reference to `cos' /opt/NAG/cll3a09dgl/lib/libnagc_nag.so: undefined reference to `log10' collect2: error: ld returned 1 exit status make: *** [CppLinkErrorUndefinedReferenceToSqrt] Error 1 11:11:40: The process "/usr/bin/make" exited with code 2. Error while building/deploying project CppLinkErrorUndefinedReferenceToSqrt (target: Desktop) When executing step 'Make'
This link error occurred when
- compiling to C (see How to use Qt Creator to compile C code?)
- using the NAG C library
The most common solution to this link error would be to add the following line to your Qt project file:
In this case, however, this did not work.
- Download the Qt Creator project 'CppLinkErrorUndefinedReferenceToSqrt' with the problem (zip)
- Download the Qt Creator project 'CppLinkErrorUndefinedReferenceToSqrt' with the solution (zip)
Operating system(s) or programming environment(s)
Lubuntu 12.10 (quantal)
Qt Creator 2.5.2
- G++ 4.7.2
Libraries used:
STL: GNU ISO C++ Library, version
4.7.2
Qt project file: CppLinkErrorUndefinedReferenceToSqrt.pro
QT -= core gui INCLUDEPATH += /opt/NAG/cll3a09dgl/include LIBS += -L/opt/NAG/cll3a09dgl/lib -lnagc_nag #Compile with GNU C compiler QMAKE_CXX = gcc QMAKE_CXXFLAGS = -x c CONFIG += console CONFIG -= app_bundle TEMPLATE = app SOURCES += main.cpp
#include <math.h> #include <nag.h> #include <nag_stdlib.h> ///C code that is invalid C++ code struct template { int new; struct template* class; }; void test() { struct template t; t.new += 1; t.class = 0; } /* For C compiler */ int main(void) { char * s = 0; s = NAG_ALLOC(31,char); if (!s) { /* ... */ return 1; } /* ... */ NAG_FREE(s); return 0; }
Add the following two lines to your project file: