[Chapter 3] 3.2.166 sysread
Author: Larry Wall, Tom Christiansen & Randal L. Schwartz
Date: 1999-07-02T01:55:14Z

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| Chapter 3 Functions |

### 3.2.166 sysread

    sysread FILEHANDLE, SCALAR, LENGTH, OFFSET
    sysread FILEHANDLE, SCALAR, LENGTH

This function attempts to read `LENGTH` bytes of data into variable `SCALAR` from the specified `FILEHANDLE` using read(2). The function returns the number of bytes actually read, or 0 at EOF. It returns the undefined value on error. `SCALAR` will be grown or shrunk to the length actually read. The `OFFSET`, if specified, says where in the string to start putting the bytes, so that you can read into the middle of a string that's being used as a buffer. For an example, see syswrite. You should be prepared to handle the problems (like interrupted system calls) that standard I/O normally handles for you. Also, do not mix calls to read and sysread on the same filehandle unless you are into heavy wizardry (and/or pain).

3.2.165 sysopen |  | 3.2.167 system