Errors in linking during build with Core Plot

Question

I have just added a Core Plot view to my application based on a tutorial (http://www.switchonthecode.com/tutorials/using-core-plot-in-an-iphone-application). I have put the Core Plot drawing code in the windowDidLoad method of the window controller for the window where I have included the CPLayerHostingView. The code for the plot is:

CPXYPlotSpace *plotSpace = (CPXYPlotSpace *)graph.defaultPlotSpace;
plotSpace.xRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(-6) 
                                               length:CPDecimalFromFloat(12)];
plotSpace.yRange = [CPPlotRange plotRangeWithLocation:CPDecimalFromFloat(-5) 
                                               length:CPDecimalFromFloat(30)];

CPXYAxisSet *axisSet = (CPXYAxisSet *)graph.axisSet;

CPLineStyle *lineStyle = [CPLineStyle lineStyle];
lineStyle.lineColor = [CPColor blackColor];
lineStyle.lineWidth = 2.0f;

axisSet.xAxis.majorIntervalLength = [[NSDecimalNumber decimalNumberWithString:@"5"] decimalValue];  
axisSet.xAxis.minorTicksPerInterval = 4;
axisSet.xAxis.minorTicksPerInterval = 4;
axisSet.xAxis.majorTickLineStyle = lineStyle;
axisSet.xAxis.minorTickLineStyle = lineStyle;
axisSet.xAxis.axisLineStyle = lineStyle;
axisSet.xAxis.minorTickLength = 5.0f;
axisSet.xAxis.majorTickLength = 7.0f;
axisSet.xAxis.axisLabelOffset = 3.0f;

axisSet.yAxis.majorIntervalLength = [[NSDecimalNumber decimalNumberWithString:@"5"] decimalValue];  
axisSet.yAxis.minorTicksPerInterval = 4;
axisSet.yAxis.minorTicksPerInterval = 4;
axisSet.yAxis.majorTickLineStyle = lineStyle;
axisSet.yAxis.minorTickLineStyle = lineStyle;
axisSet.yAxis.axisLineStyle = lineStyle;
axisSet.yAxis.minorTickLength = 5.0f;
axisSet.yAxis.majorTickLength = 7.0f;
axisSet.yAxis.axisLabelOffset = 3.0f;

CPScatterPlot *xSquaredPlot = [[[CPScatterPlot alloc] 
                                initWithFrame:graph.defaultPlotSpace.bounds] autorelease];
xSquaredPlot.identifier = @"X Squared Plot";
xSquaredPlot.dataLineStyle.lineWidth = 1.0f;
xSquaredPlot.dataLineStyle.lineColor = [CPColor redColor];
xSquaredPlot.dataSource = self;
[graph addPlot:xSquaredPlot];

When I build I get the following errors:

".objc_class_name_CPPlotRange", referenced from: literal-pointer@__OBJC@__cls_refs@CPPlotRange in HistogramWindowController.o

"_CPDecimalFromFloat", referenced from: -[HistogramWindowController windowDidLoad] in HistogramWindowController.o -[HistogramWindowController windowDidLoad] in HistogramWindowController.o -[HistogramWindowController windowDidLoad] in HistogramWindowController.o -[HistogramWindowController windowDidLoad] in HistogramWindowController.o

".objc_class_name_CPLineStyle", referenced from: literal-pointer@__OBJC@__cls_refs@CPLineStyle in HistogramWindowController.o

".objc_class_name_CPXYGraph", referenced from: literal-pointer@__OBJC@__cls_refs@CPXYGraph in HistogramWindowController.o

".objc_class_name_CPScatterPlot", referenced from: literal-pointer@__OBJC@__cls_refs@CPScatterPlot in HistogramWindowController.o

".objc_class_name_CPPlotSymbol", referenced from: literal-pointer@__OBJC@__cls_refs@CPPlotSymbol in HistogramWindowController.o

".objc_class_name_CPColor", referenced from: literal-pointer@__OBJC@__cls_refs@CPColor in HistogramWindowController.o

".objc_class_name_CPFill", referenced from: literal-pointer@__OBJC@__cls_refs@CPFill in HistogramWindowController.o

ld: symbol(s) not found collect2: ld returned 1 exit status

I've never encountered an error like this. Can anyone shed any light on what the problem might be?

Cheers

Answer 1

It means you haven't linked in the framework correctly. You've probably just added the framework to your project, #imported the header, but forgot to make sure that the framework is actually getting linked into your target.

Answer 2

There are some instructions on this wiki page for incorporating the framework into Mac projects. If you follow those, you should be able to avoid any problems with linking in the framework.