# slow5_hdr_write ## NAME slow5_hdr_write - writes the associated SLOW5 header to a SLOW5 file ## SYNOPSYS `int slow5_hdr_write(slow5_file_t *s5p)` ## DESCRIPTION `slow5_hdr_write()` writes the associated SLOW5 header to the SLOW5 file pointed by *s5p*. The associated SLOW5 header is the *s5p->header* member inside the *slow5_file_t \*s5p* returned by `slow5_open()`. ## RETURN VALUE Upon successful completion, `slow5_hdr_write()` returns the number of bytes written. Otherwise, a negative value is returned. ## ERRORS todo ## NOTES In the future a error number will be set to indicate the error. ## EXAMPLES ``` #include #include #include #define FILE_PATH "test.slow5" int main(){ slow5_file_t *sp = slow5_open(FILE_PATH, "w"); if(sp==NULL){ fprintf(stderr,"Error opening file!\n"); exit(EXIT_FAILURE); } slow5_hdr_t* header = sp->header; //add a header group attribute called run_id if (slow5_hdr_add("run_id", header) != 0){ fprintf(stderr,"Error adding run_id attribute\n"); exit(EXIT_FAILURE); } //set the run_id attribute to "run_0" for read group 0 if (slow5_hdr_set("run_id", "run_0", 0, header) != 0){ fprintf(stderr,"Error setting run_id attribute in read group 0\n"); exit(EXIT_FAILURE); } //add auxilliary field: channel number if (slow5_aux_add("channel_number", SLOW5_STRING, sp->header) < 0){ fprintf(stderr,"Error adding channel_number auxilliary field\n"); exit(EXIT_FAILURE); } if(slow5_hdr_write(sp) < 0){ fprintf(stderr,"Error writing header!\n"); exit(EXIT_FAILURE); } slow5_close(sp); return 0; } ```