Seeking clarification: function within if conditional Post: 302992312

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Top Forums UNIX for Beginners Questions & Answers Seeking clarification: function within if conditional Post 302992312 by Scrutinizer on Thursday 23rd of February 2017 03:56:58 PM

02-23-2017

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The if conditional construct check the exit status of the
command or set of commands that it executes. A command that successfully executes without error returns a zero exit status.

If this value is 0, then the "then" commands will be executed. If the return code is anything else (i.e. an error condition occurred), then the "else" commands will be executed.

Quote:

Originally Posted by strategery

Correct me if I mis-understand, but you're saying that basically the 'if' evaluator of bash makes the determination that it has been passed a command, and that an exit status of '0' should equate to true for that conditional? In other words, I think I've been viewing 'if' as a pure boolean test, when in fact it's much smarter....?

Code:

The if command shall execute a compound-list and use its exit status to determine whether to execute another compound-list.

The format for the if construct is as follows:

if compound-listthen
    compound-list[elif compound-listthen
    compound-list] ...
[else
    compound-list]


fi

The if compound-list shall be executed; if its exit status is zero, the then compound-list shall be executed and the command shall complete. 
Otherwise, each elif compound-list shall be executed, in turn, and if its exit status is zero, the then compound-list shall be executed and 
the command shall complete. Otherwise, the else compound-list shall be executed.

Shell Command Language: The if Conditional Construct

Last edited by Scrutinizer; 02-23-2017 at 05:04 PM..

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LEARN ABOUT REDHAT

xmregistersegmentencoding

XmRegisterSegmentEncoding(library call) 								   XmRegisterSegmentEncoding(library call)

NAME

       XmRegisterSegmentEncoding  --  A  compound string function that registers a compound text encoding format for a specified font list element
       tag

SYNOPSIS

       #include <Xm/Xm.h>
       char * XmRegisterSegmentEncoding(
       char *fontlist_tag,
       char *ct_encoding);

DESCRIPTION

       XmRegisterSegmentEncoding registers a compound text encoding format with the specified font list element tag. The  XmCvtXmStringToCT  func-
       tion  uses  this  registry to map the font list tags of compound string segments to compound text encoding formats. Registering a font list
       tag that already exists in the registry overwrites the original entry. You can unregister a font list tag by passing a NULL value  for  the
       ct_encoding parameter.

       fontlist_tag
		 Specifies the font list element tag to be registered. The tag must be a NULL-terminated ISO8859-1 string.

       ct_encoding
		 Specifies  the  compound  text  character set to be used for segments with the font list tag. The value must be a NULL-terminated
		 ISO8859-1 string.  A value of XmFONTLIST_DEFAULT_TAG maps the specified font list tag to the code set of the locale.

RETURN

       Returns NULL for a new font list tag or the old ct_encoding value for an already registered font list tag. The application  is  responsible
       for freeing the storage associated with the returned data (if any) by calling XtFree.

RELATED

       XmCvtXmStringToCT(3), XmFontList(3), XmMapSegmentEncoding(3), and XmString(3).

													   XmRegisterSegmentEncoding(library call)