undefined-reference

问题 I'm trying to link OpenBLAS library with MinGW w64 compiler on Windows. This is my code: #include <cstdio> #include <cblas.h> #include <cstdlib> int main(){ double m[10],n[10]; int i, result; for(i=0;i<10;i++) m[i] = 1.0l*rand()/RAND_MAX; for(i=0;i<10;i++) n[i] = 1.0l*rand()/RAND_MAX; result = cblas_ddot(10, m, 1, n, 1); return 0; } and compiling with this command: g++ ^ -IC:\OpenBLAS-0.3.6-x64\include -LC:\OpenBLAS-0.3.6-x64\lib -lopenblas blas.cpp and get an error undefined reference to

问题 I've installed clang 3.2 on my Ubuntu 13.04 machine, and have compiled and built libc++, and everything is in place. However, when I try to link my (really simple) code, the linker reports that references to std::cout etc. are undefined. If anyone could advise me what I could do to solve this, I'd be very grateful -- I've tried everything I can think of. The commands and output are here: $ clang++ -v -stdlib=libc++ -lpthread -ldl sqlite3/sqlite3.o src/world.o -o bin/world Ubuntu clang version

问题 I've installed clang 3.2 on my Ubuntu 13.04 machine, and have compiled and built libc++, and everything is in place. However, when I try to link my (really simple) code, the linker reports that references to std::cout etc. are undefined. If anyone could advise me what I could do to solve this, I'd be very grateful -- I've tried everything I can think of. The commands and output are here: $ clang++ -v -stdlib=libc++ -lpthread -ldl sqlite3/sqlite3.o src/world.o -o bin/world Ubuntu clang version

问题 I'm using CMAKE to build OpenALPR, which uses OpenCV. My CMakeLists.txt contains, among other, the following statements : # Discover OpenCV directory automatically find_path(OpenCV_DIR NAMES OpenCVConfig.cmake HINTS ${CMAKE_SOURCE_DIR}/../libraries/opencv/ /storage/projects/alpr/libraries/opencv/ ) # Opencv Package FIND_PACKAGE( OpenCV REQUIRED ) #Some code omitted for clarity ... TARGET_LINK_LIBRARIES(alpr ${OPENALPR_LIB} ${STATE_DETECTION_LIB} support video ${OpenCV_LIBS} ${Tesseract

问题 I cannot figure out why this is not working. I will put up all three of my files and possibly someone can tell me why it is throwing this error. I am using g++ to compile the program. Program: #include <iostream> #include "h8.h" using namespace std; int main() { char sentence[MAX_SENTENCE_LENGTH]; char writeTo[] = "output.txt"; int distanceTo,likePosition, length, numWords; cout << "ENTER A SENTENCE! "; cin.getline(sentence, 299); length = strlen(sentence); numWords = wordCount(sentence,

问题 I am trying to develop a program that communicates with a PCSC USB reader using Conan and CMake with the LibLogicalAccess library. I followed the instructions of building and installing the library which seemed to have gone fine. I created a small simple console project with a "main.cpp" file. Following the C++ guide on the wiki of the library I tried to call a function from the library which resulted in a "Undefined reference to function . I know there are a lot of topics covering this but I

问题 What are undefined reference/unresolved external symbol errors? What are common causes and how to fix/prevent them? Feel free to edit/add your own. 回答1: Compiling a C++ program takes place in several steps, as specified by 2.2 (credits to Keith Thompson for the reference): The precedence among the syntax rules of translation is specified by the following phases [see footnote] . Physical source file characters are mapped, in an implementation-defined manner, to the basic source character set

问题 I am using cmake to build my project, but I am getting these errors. Scanning dependencies of target las2vtk [ 50%] Building CXX object CMakeFiles/las2vtk.dir/LAS2VTK.cxx.o [100%] Building CXX object CMakeFiles/las2vtk.dir/PointSet.cxx.o Linking CXX executable las2vtk CMakeFiles/las2vtk.dir/LAS2VTK.cxx.o: In function `main': LAS2VTK.cxx:(.text+0xf1): undefined reference to `PointSet<PointND<3, float> >::read_LAS(std::basic_string<char, std::char_traits<char>, std::allocator<char> >&, int)'

问题 I am using cmake to build my project, but I am getting these errors. Scanning dependencies of target las2vtk [ 50%] Building CXX object CMakeFiles/las2vtk.dir/LAS2VTK.cxx.o [100%] Building CXX object CMakeFiles/las2vtk.dir/PointSet.cxx.o Linking CXX executable las2vtk CMakeFiles/las2vtk.dir/LAS2VTK.cxx.o: In function `main': LAS2VTK.cxx:(.text+0xf1): undefined reference to `PointSet<PointND<3, float> >::read_LAS(std::basic_string<char, std::char_traits<char>, std::allocator<char> >&, int)'

问题 Am facing a problem that may be slightly complicated to explain and understand as giving the entire picture would be too big and difficult. Please excuse me for it. Consider the following Makefile: all: clients.so simulator backup LD_PRELOAD=/home/Juggler/client/clients.so ./simulator backup: backup.c libclient.a gcc backup.c -o backup -L /home/Juggler/client -L. -lclient -ldl simulator: simulator.c libclient.a gcc -g simulator.c -o simulator -L /home/Juggler/client -L. -lclient -ldl -pthread