reading bam files in C using htslib

readBam.C

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <htslib/sam.h>

int main(int argc, char *argv[]){
	
	samFile *fp_in = hts_open(argv[1],"r"); //open bam file
	bam_hdr_t *bamHdr = sam_hdr_read(fp_in); //read header
	bam1_t *aln = bam_init1(); //initialize an alignment
	
	char *chrom = argv[2];
	int locus = atoi(argv[3]);
	int comp ;

	printf("%s\t%d\n", chrom, locus);

	//header parse
	//uint32_t *tar = bamHdr->text ;
	//uint32_t *tarlen = bamHdr->target_len ;

	//printf("%d\n",tar);
	
	while(sam_read1(fp_in,bamHdr,aln) > 0){
		
		int32_t pos = aln->core.pos +1; //left most position of alignment in zero based coordianate (+1)
		char *chr = bamHdr->target_name[aln->core.tid] ; //contig name (chromosome)
		uint32_t len = aln->core.l_qseq; //length of the read.
		
		uint8_t *q = bam_get_seq(aln); //quality string
		uint32_t q2 = aln->core.qual ; //mapping quality
		
		
		char *qseq = (char *)malloc(len);

		for(int i=0; i< len ; i++){
			qseq[i] = seq_nt16_str[bam_seqi(q,i)]; //gets nucleotide id and converts them into IUPAC id.
		}
		
		//printf("%s\t%d\t%d\t%s\t%s\t%d\n",chr,pos,len,qseq,q,q2);

		 if(strcmp(chrom, chr) == 0){

			 if(locus > pos+len){
				 printf("%s\t%d\t%d\t%s\t%s\t%d\n",chr,pos,len,qseq,q,q2);
			 }
		 }
	}
	
	bam_destroy1(aln);
	sam_close(fp_in);
	
	return 0;
}