make: Nothing to be done for `all' on Eclipse CDT

Question

I'm trying to learn OpenCV following this tutorial. But I cannot build the project.

When I try to build all I get this error:

22:49:54 **** Incremental Build of configuration Debug for project OpenCVLearning ****
make all 
make: Nothing to be done for `all'.

22:49:55 Build Finished (took 135ms)

When I try to run I get this message:

terminate called after throwing an instance of 'std::logic_error'
  what():  basic_string::_S_construct null not valid

Here is the content of the Make file:

################################################################################
# Automatically-generated file. Do not edit!
################################################################################

-include ../makefile.init

RM := rm -rf

# All of the sources participating in the build are defined here
-include sources.mk
-include src/subdir.mk
-include subdir.mk
-include objects.mk

ifneq ($(MAKECMDGOALS),clean)
ifneq ($(strip $(C++_DEPS)),)
-include $(C++_DEPS)
endif
ifneq ($(strip $(C_DEPS)),)
-include $(C_DEPS)
endif
ifneq ($(strip $(CC_DEPS)),)
-include $(CC_DEPS)
endif
ifneq ($(strip $(CPP_DEPS)),)
-include $(CPP_DEPS)
endif
ifneq ($(strip $(CXX_DEPS)),)
-include $(CXX_DEPS)
endif
ifneq ($(strip $(C_UPPER_DEPS)),)
-include $(C_UPPER_DEPS)
endif
endif

-include ../makefile.defs

# Add inputs and outputs from these tool invocations to the build variables 

# All Target
all: OpenCVLearning

# Tool invocations
OpenCVLearning: $(OBJS) $(USER_OBJS)
    @echo 'Building target: $@'
    @echo 'Invoking: GCC C++ Linker'
    g++ -L/usr/local/lib -o "OpenCVLearning" $(OBJS) $(USER_OBJS) $(LIBS)
    @echo 'Finished building target: $@'
    @echo ' '

# Other Targets
clean:
    -$(RM) $(OBJS)$(C++_DEPS)$(C_DEPS)$(CC_DEPS)$(CPP_DEPS)$(EXECUTABLES)$(CXX_DEPS)$(C_UPPER_DEPS) OpenCVLearning
    -@echo ' '

.PHONY: all clean dependents
.SECONDARY:

-include ../makefile.targets

Source code:

#include <cv.h>
#include <highgui.h>

using namespace cv;

int main( int argc, char** argv )
{
  Mat image;
  image = imread( argv[1], 1 );

  if( argc != 2 || !image.data )
    {
      printf( "No image data \n" );
      return -1;
    }

  namedWindow( "Display Image", CV_WINDOW_AUTOSIZE );
  imshow( "Display Image", image );

  waitKey(0);

  return 0;
}

Why is it happening? How could I solve this?

Answer 1

This is not a problem

make: Nothing to be done for `all'.

it just means, that everything is already built and you're ready to go and test your executable.

The second one

terminate called after throwing an instance of 'std::logic_error'  
  what():  basic_string::_S_construct null not valid

is a runtime error.

It says, that somewhere you or OpenCV pass a NULL pointer to a std::string constructor, which is not allowed.

The only place, where this could happen in your code, might be

image = imread( argv[1], 1 );

when you call the executable without parameters. In this case argc is one and argv[1] is NULL.