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bl_gff3_index_add(3)	   Library Functions Manual	  bl_gff3_index_add(3)

NAME
       bl_gff3_index_add() - Add a GFF3	feature	to an in-memory	index

LIBRARY
       #include	<biolibc/gff3-index.h>
       -lbiolibc -lxtend

SYNOPSIS
       int     bl_gff3_index_add(bl_gff3_index_t *gi, bl_gff3_t	*feature)

ARGUMENTS
       gi      Pointer to gff3_index_t object to which a record	will be	added
       feature Pointer to GFF feature to be indexed

DESCRIPTION
       The  gff3_index_t  class	 maintains an in-memory	index of GFF features,
       containing the GFF fields SEQ_ID, START,	and END, and the  offset  into
       the  file as reported by	ftell(3), or by	bl_gff3_read(3), which records
       the file	position of each GFF feature it	reads.

       bl_gff3_index_add_pos(3)	adds a GFF feature with	file position file_pos
       to the index.  Features of interest, perhaps only genes or only	exons,
       can  be	added to the index on-the fly while reading through a GFF file
       with bl_gff3_read(3).

       The index can later be searched or traversed  forward  or  backward  to
       quickly find the	location of a feature and reposition a FILE pointer to
       it  using  fseek(3).   This  system eliminates the need to inhale large
       numbers of GFF features into memory.

RETURN VALUES
       BL_GFF3_INDEX_OK	on success, BL_GFF3_MALLOC_FAILED if memory could  not
       be allocated

EXAMPLES
       bl_gff3_index_t	gi;
       bl_gff3_t	feature;

       if ( bl_gff3_read(&feature, gff3_stream,	BL_GFF3_FIELD_ALL) == BL_READ_OK )
       {
	   if (	bl_gff3_index_add(&gi, &feature) != BL_GFF3_INDEX_OK )
	       fprintf(stderr, "Error addind to	GFF index.n");
       }

SEE ALSO
       bl_gff3_index_seek_reverse(3), bl_gff3_read(3)

							  bl_gff3_index_add(3)

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