Htslib is a unified c library for accessing common file formats, such as sam (sequence alignment/map) and vcf (variant call format), used for nucleic acid sequence data obtained by high-throughput sequencing.

htslib implements a generalized bam (binary sam) index. the htslib file reader first looks for the new index and then for the old if the new index is absent.

htslib is still experimental. it has not been tested on large-scale real data. some useful apis are missing.