Re: questions about system function: mmap / fwrite

[Helge Hafting <helge.hafting@aitel.hist.no>]

sylvanino b wrote:

> Hello,
>
> I have a question about ways of accessing a file. 
>
> I know it is possible to use: fseek + fwrite/fread to access a file.
> and It is also possible to map file in memory with  "mmap" function,
> and access it by adressing memory.
>
> Currently I use the frame buffer of  mobile phones with mmap function.
> For my understanding, I would like to know what is the difference
> between using fseek+fwrite compared to mmap style.
> Dont hesitate to be precise or to use technical terms.
>
> Thanks you,
>  
There may be subtle performance differences, but I'd say the most
important here is to use the API that best suits the problem at hand.
fwrite/fread is sequential in nature, useful when you want to read/write
large contigous chunks of data, and when the notion of a "current position"
in the file is useful.

mmap is nice when you find it useful to access the file as a random-access
array of bytes. mmap style access seems to be the best fit for a 
framebuffer.

Helge Hafting

Helge Hafting

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