# %read() function

The %read() function reads the number
of bytes designated in *size* into *var*, from the file specified by *file.descriptor*.
This file is returned by a previous call to %open(), %creat(), or %dup().

Note: When using this function with sockets: For UNIX: Use the socket descriptor that results from
the %accept() function call. For Windows: Use the %recv() function.

## Syntax

```
n = %read(file.descriptor, var, size)
```

## Description

A string of a size at least
equal to *size* must have been assigned to *var* before the call by either an explicit assignment (for
example, `buffer=space(1000)`) or by the char
reserve statement, or else the data is truncated.

This function returns the number of bytes actually read. If the bytes
returned are less than *size*, the content of the
trailing string is undefined, as is normal in C. No data translation
occurs. If the data read in *var* contains segment
marks (x’ff’), results are unpredictable. Use %malloc() to obtain a memory block in which to read binary data.

## Example(s)

```
item=’’
char buffer[10000] ;* reserve buffer space
loop while true do
 n=%read(fd, buffer, 10000)
 if n=-1 then
 print "Error ":system(0)
 stop
 end else
 if n<10000 then
 * The whole file has been read.
 item=item:buffer[1,n]
 convert char(10) to char(254) in item
 write item on itemname
 stop
 end else
 * Some more to read
 item=item:buffer
 end
end
repeat
```

## See also

- [%bind() function](https://d3codex.com/pickbasic-flashbasic/percent-bind-function/)
- [%creat() function](https://d3codex.com/pickbasic-flashbasic/percent-creat-function/)
- [%dup() function](https://d3codex.com/pickbasic-flashbasic/percent-dup-function/)
- [%listen() function](https://d3codex.com/pickbasic-flashbasic/percent-listen-function/)
- [%lseek() function](https://d3codex.com/pickbasic-flashbasic/percent-lseek-function/)
- [%malloc() function](https://d3codex.com/pickbasic-flashbasic/percent-malloc-function/)
- [%open() function](https://d3codex.com/pickbasic-flashbasic/percent-open-function/)
- [%rdhex() function](https://d3codex.com/pickbasic-flashbasic/percent-rdhex-function/)
- [%ttyname() function](https://d3codex.com/pickbasic-flashbasic/percent-ttyname-function/)
- [FlashBASIC C functions overview](https://d3codex.com/pickbasic-flashbasic/flashbasic-c-functions-overview/)
- [cfunction statement](https://d3codex.com/pickbasic-flashbasic/cfunction-statement/)

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Source: https://d3codex.com/pickbasic-flashbasic/percent-read-function/ - part of the D3Codex reference.