! Aware to Perl: wantarray may return undef

RocketAware > Perl >

wantarray may return undef

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, ...

wantarray may return undef

The wantarray operator returns true if a subroutine is expected to return a list, and false otherwise. In Perl 5.004, wantarray can also return the undefined value if a subroutine's return value will not be used at all, which allows subroutines to avoid a time-consuming calculation of a return value if it isn't going to be used.

Source: what's new for perl5.004
Copyright: Larry Wall, et al.

Next: Changes to tainting checks

Previous: No resetting of $. on implicit close

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

[Overview Topics]

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