KLT_FeatureList

typedef struct {
int nFeatures;
KLT_Feature *feature;
} *KLT_FeatureList;

A KLT_FeatureList is an array of features. The nFeatures field indicates the number of features allocated, but not necessarily the number of non-lost features. It must not be changed manually.

NOTE: Although a feature list and a feature history look similar, the former is intended to refer to an array of features from a single image, while the latter refers to the same feature tracked through several images.

The following code illustrates how to access the data in a feature list: 

KLT_FeatureList fl;
int feat;

for (feat = 0 ; feat < fl->nFeatures ; feat++)  {
     printf("(%5.1f,%5.1f) = %d\n",
          fl->feature[feat]->x,
          fl->feature[feat]->y,
          fl->feature[feat]->val);
}