Some questions regarding old if.c Post: 302930427

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Top Forums Programming Some questions regarding old if.c Post 302930427 by orbit on Saturday 3rd of January 2015 08:27:54 PM

01-03-2015

Registered User

Thank you ongoto and thank you achenle for your great explanation Smilie

I worked really hard on understanding the code and I nearly got everything.
This is the last part I do not understand:

Code:

if(eq(a, "{")) { /* execute a command for exit code */
    if(fork()) /*parent*/ wait(&ccode);
    else { /*child*/
        doex(1);
        goto err;
    }
    while((a=nxtarg()) && (!eq(a,"}")));
    return(ccode? 0 : 1);
}

As described in the man-page (if page from Section 1 of the unix-6th manual), if we put the command in brackets "if expr { command } ", we can obtain his exit code.

So we fork the current process, and then wait for our child process to finish? But where is our child process continuing his work? After the fork, we will go into the while-loop and and just skip some arguments and then return with ccode? Where was ccode changed? What is ccode?

Could you please explain me this the given code snippet? And elaborate on ccode?

The man page of wait: wait page from Section 2 of the unix-6th manual
The source code: [C] code - Pastebin.com

Thank you very much Smilie

orbit

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html::formhandler::field::display

HTML::FormHandler::Field::Display(3pm)			User Contributed Perl Documentation		    HTML::FormHandler::Field::Display(3pm)

NAME

       HTML::FormHandler::Field::Display - display only field

VERSION

       version 0.40013

SYNOPSIS

       This class can be used for fields that are display only. It will render the value returned by a form's 'html_<field_name>' method, or the
       field's 'html' attribute.

	 has_field 'explanation' => ( type => 'Display',
	    html => '<p>This is an explanation...</p>' );

       or in a form:

	 has_field 'explanation' => ( type => 'Display' );
	 sub html_explanation {
	    my ( $self, $field ) = @_;
	    if( $self->something ) {
	       return '<p>This type of explanation...</p>';
	    }
	    else {
	       return '<p>Another type of explanation...</p>';
	    }
	 }
	 #----
	 has_field 'username' => ( type => 'Display' );
	 sub html_username {
	     my ( $self, $field ) = @_;
	     return '<div><b>User:&nbsp;</b>' . $field->value . '</div>';
	 }

       or set the name of the rendering method:

	  has_field 'explanation' => ( type => 'Display', set_html => 'my_explanation' );
	  sub my_explanation {
	    ....
	  }

       You can also supply an 'html' method with a trait or a custom field. See examples in t/field_traits.t and t/xt/display.t of the
       distribution.

AUTHOR

       FormHandler Contributors - see HTML::FormHandler

COPYRIGHT AND LICENSE

       This software is copyright (c) 2012 by Gerda Shank.

       This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

perl v5.14.2							    2012-06-25				    HTML::FormHandler::Field::Display(3pm)