# _CP_readv

_CP_readv is equivalent to the readv BASIC statement.

Depending upon type, _CP_read acts
as these BASIC commands:

| Type | BASIC Statement |
| --- | --- |
| _CP_READV | readv result from expression1, string, expression2 |
| _CP_READVU | readvu result from expression1, string, expression2 |
| _CP_READVUL | readvu result from expression, string, expression2 |

## Syntax

```
int _CP_readv(int type, CPSTR** result, int expression1, CPSTR* string,
int expression2, int* value)
```
The *value* parameter returns a 1 if
the item is locked. If *value* is not needed, the
user can pass `(int*) 0`.

The _CP_readv call uses the same optimized read routine as
BASIC, which is faster than using AQL and BASIC. *expression1* should be an integer file descriptor returned by the _CP_open call.

## Description

This function returns -1 if
an error occurs. The error code is contained in _CP_errno. If the attribute number is bad, then _CP_errno will contain PE_BADATTR.

## Example(s)

```
/* Reads the first attribute of the item "myid" from "myfile". */

CPSTR * s = _CP_mkstr("myfile");
CPSTR * id = _CP_mkstr("myid");
CPSTR * xx = _CP_str_null;
int f;

_CP_open(&f,_CP_str_null,s);
_CP_readv(_CP_READV, xx, f, id, 1, 0);
```

## See also

- [C functions overview](https://d3codex.com/cfunctions/c-functions-overview/)
- [_CP_writev](https://d3codex.com/cfunctions/cp-writev/)

---
Source: https://d3codex.com/cfunctions/cp-readv/ - part of the D3Codex reference.