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Re: Program crashing on declaring large char array

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On 06/18/17 04:34 PM, Ian Collins wrote:
> On 06/18/17 04:11 PM, DFS wrote:
>> I'm reading in a .csv file, counting the lines, and allocating arrays
>> based on the line count.
>>
>> I want a multidimensional array of N rows (lines) by 5 columns.  I need
>> each address in the array to store up to 25 characters.
>>
>> char data[lines][5][25];
>>
>> If the .csv file is small (few dozen lines) it works, but if the .csv
>> file has 10,000 lines, it crashes.
>>
>> I assume it has something to do with memory allocation.
>
> It doesn't have anything to do with memory allocation because you don't
> allocate any memory!
>
> What is does show is you have exceed the stack size (let's assume there
> is a stack...) limit for your implementation.
>
>> char data[lines][5][25] = malloc(lines * 5 * 25);  says 'Variable length
>> array cannot be initialized'
>
> Assuming "lines" isn't a compile time constant, you are creating a
> variable length array (VLA) which, as your compiler is happy to report,
> can not be initialised.
>
> You need to allocate a block of rows, something like:
>
> typedef char Row[5][25];
>
> Row* data = malloc( lines * sizeof *stuff );

Rubbish cut-n-paste:

Row* data = malloc( lines * sizeof *data );

-- 
Ian

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Thread

Program crashing on declaring large char array DFS <nospam@dfs.com> - 2017-06-18 00:11 -0400
  Re: Program crashing on declaring large char array Ian Collins <ian-news@hotmail.com> - 2017-06-18 16:34 +1200
    Re: Program crashing on declaring large char array Ian Collins <ian-news@hotmail.com> - 2017-06-18 16:36 +1200
  Re: Program crashing on declaring large char array Barry Schwarz <schwarzb@dqel.com> - 2017-06-17 21:39 -0700
  Re: Program crashing on declaring large char array GOTHIER Nathan <nathan.gothier@gmail.com> - 2017-06-18 09:51 +0200
  Re: Program crashing on declaring large char array already5chosen@yahoo.com - 2017-06-18 03:49 -0700
    Re: Program crashing on declaring large char array already5chosen@yahoo.com - 2017-06-18 03:55 -0700
    Re: Program crashing on declaring large char array supercat@casperkitty.com - 2017-06-19 09:25 -0700
  Re: Program crashing on declaring large char array James Kuyper <jameskuyper@verizon.net> - 2017-06-18 14:10 -0400

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