# slow5_xx
## NAME
slow5_xx - fetches a record from a SLOW5 file corresponding to a given read ID
## SYNOPSYS
`int slow5_xx(const char *read_id, slow5_rec_t **read, slow5_file_t *s5p)`
## DESCRIPTION
`slow5_xx()` fetches a record from a SLOW5 file *s5p* for a specified *read_id* into a *slow5_rec_t* and stores the address of the *slow5_rec_t* in **read*.
## RETURN VALUE
Upon successful completion, `slow5_xx()` returns a non negative integer (>=0). Otherwise, a negative value is returned that indicates the error and `slow5_errno` is set to indicate the error.
## ERRORS
* `SLOW5_ERR_ARG`
Invalid argument - read_id, read or s5p is NULL.
## NOTES
`slow5_xx()` internally uses `pread()`.
## EXAMPLES
```
#include <stdio.h>
#include <stdlib.h>
#include <slow5/slow5.h>
#define FILE_PATH "examples/example.slow5"
#define TO_PICOAMPS(RAW_VAL,DIGITISATION,OFFSET,RANGE) (((RAW_VAL)+(OFFSET))*((RANGE)/(DIGITISATION)))
int main(){
slow5_file_t *sp = slow5_open(FILE_PATH,"r");
if(sp==NULL){
fprintf(stderr,"Error in opening file\n");
exit(EXIT_FAILURE);
}
slow5_rec_t *rec = NULL;
int ret=0;
ret = slow5_idx_load(sp);
if(ret<0){
fprintf(stderr,"Error in loading index\n");
exit(EXIT_FAILURE);
}
ret = slow5_get("r3", &rec, sp);
if(ret < 0){
fprintf(stderr,"Error when fetching the read\n");
}
else{
printf("%s\t",rec->read_id);
uint64_t len_raw_signal = rec->len_raw_signal;
for(uint64_t i=0;i<len_raw_signal;i++){
double pA = TO_PICOAMPS(rec->raw_signal[i],rec->digitisation,rec->offset,rec->range);
printf("%f ",pA);
}
printf("\n");
}
slow5_rec_free(rec);
slow5_idx_unload(sp);
slow5_close(sp);
}
```
## SEE ALSO
[slow5_yy()](slow5_yy.md), [slow5_yy()](slow5_yy.md)