! Aware to Perl: Why can't my script read from STDIN after I gave it EOF (^D on Unix, ^Z on MS-DOS)?

RocketAware > Perl >

Why can't my script read from STDIN after I gave it EOF (^D on Unix, ^Z on MS-DOS)?

Tips: Browse or Search all pages for efficient awareness of Perl functions, operators, and FAQs.

Home

Search Perl pages

Subjects

By activity
Professions, Sciences, Humanities, Business, ...

User Interface
Text-based, GUI, Audio, Video, Keyboards, Mouse, Images,...

Text Strings
Conversions, tests, processing, manipulation,...

Math
Integer, Floating point, Matrix, Statistics, Boolean, ...

Processing
Algorithms, Memory, Process control, Debugging, ...

Stored Data
Data storage, Integrity, Encryption, Compression, ...

Communications
Networks, protocols, Interprocess, Remote, Client Server, ...

Hard World
Timing, Calendar and Clock, Audio, Video, Printer, Controls...

File System
Management, Filtering, File & Directory access, Viewers, ...

Why can't my script read from STDIN after I gave it EOF (^D on Unix, ^Z on MS-DOS)?

Because some stdio's set error and eof flags that need clearing. The POSIX module defines clearerr() that you can use. That is the technically correct way to do it. Here are some less reliable workarounds:

Try keeping around the seekpointer and go there, like this:
```
    $where = tell(LOG);
    seek(LOG, $where, 0);
```
If that doesn't work, try seeking to a different part of the file and then back.
If that doesn't work, try seeking to a different part of the file, reading something, and then seeking back.
If that doesn't work, give up on your stdio package and use sysread.

Source: Perl FAQ: System Interaction
Copyright: Copyright (c) 1997 Tom Christiansen and Nathan Torkington.

Next: How can I convert my shell script to perl?

Previous: How can I call backticks without shell processing?

(Corrections, notes, and links courtesy of RocketAware.com)

[Overview Topics]

Up to: File Access

Rapid-Links: Search | About | Comments | Submit Path: RocketAware > Perl > perlfaq8/Why_can_t_my_script_read_from_ST.htm