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Re: hi, this is student studying bash. (typeset question)


From: Chet Ramey
Subject: Re: hi, this is student studying bash. (typeset question)
Date: Tue, 29 Sep 2020 09:25:45 -0400
User-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.12.0

On 9/28/20 11:40 PM, ironhopper@projfrom.me wrote:

> but I cannot find the code related it. <integer variables were signed long,
> but now 64-bit>

Arithmetic expression evaluation is in expr.c.

> the question is
> <strong> where can I find integer type definition code? <strong>

Bash variable values are strings. Greg Wooledge already explained most of
how it works.

The integer attribute is declared here:

> #define att_integer   0x040    /* internal representation is int */

and tested using this macro (sometimes inline for compound tests):

> #define integer_p(var)        ((((var)->attributes) & (att_integer)))

So if you search the source code for these identifiers, you'll find the
places integer variables are declared, set, and expanded.

-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/



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