Does C/C++ provide something like "event".

[lovecreatesbeauty]

Hello,


I want to know whether programming languages such as C or C++ provide
something like "event".

In function "f1", a handler/function "h2" is triggered. But f1 won't be
blocked by h2, f1 can execute the next task and no need to wait for
h2's return.

Does this characteristic only provided by OS like Ms Windows or Linux?


Sincerely
lovecreatesbeauty

 

[Walter Roberson]

:I want to know whether programming languages such as C or C++ provide
:something like "event".

Not as you have described it, no.

:In function "f1", a handler/function "h2" is triggered. But f1 won't be
:blocked by h2, f1 can execute the next task and no need to wait for
:h2's return.

Asynchronous execution implies one of:
- multiple CPUs
- timer-driven context switching
- cooperative multitasking
- multiple threads

None of these are considered to be requirements for either C or C++.

C in particular has defined minimal behaviours for embedded systems
that might be lacking many of the facilities you are accustomed to
in a programming language.

As far as C and C++ are concerned, those alternatives are hardware
or OS dependant, and thus not suitable candidates for standardization
as part of the language itself.


oes this characteristic only provided by OS like Ms Windows or Linux?

Threading in particular is standardized by POSIX as a library that
one can *call* from C or C++, if one's execution environment happens
to support it. A -lot- of useful features are defined as various
standardized libraries that might or might not be present on your
Apple //e's Z80 expansion card. The C and C++ languages do not
*require* these libraries: they simply provide facilities for linking
to such libraries.

Let me add another example for particular emphasis:

ANSI standard C (C89) doesn't even define open(), just fopen().

 

[EventHelix.com]

The scenario you described requires multiple threads.

In our experience, a hierarchical state machine based design
is more suitable for event driven programming.

See the following article for details:
http://www.eventhelix.com/RealtimeMantra/HierarchicalStateMachine.htm

Deepa