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copied!<p>The code is not 100% portable if you are writing memory contents to files.</p> <p>You need something called <strong>serialization</strong>. Ok, computer science term, but it basically means that you get your data and transform it into a well-defined and documented sequence of bytes, which can be read back to memory later by the same or another program. This sequence of bytes is architecture and platform-independent.</p> <p>Most Unix environments already come with a <a href="http://linux.die.net/man/3/xdr" rel="nofollow noreferrer">XDR</a> implementation, which provides routines for data serialization.</p> <p>A simple example encoding 4 doubles to stdout (you can use shell redirection, or use fopen() to open a file instead of stdout):</p> <pre><code>XDR xdrs; double data[4] = { 1.0, 255.41, -357.1, 123.4 }; int i; xdrstdio_create(&xdrs, stdout, XDR_ENCODE); for (i = 0; i < 4; i++) xdr_double(&xdrs, &data[i]); </code></pre> <p>Now, to get these doubles back (from stdin) and print them:</p> <pre><code>XDR xdrs; double data; int i; xdrstdio_create(&xdrs, stdin, XDR_DECODE); for (i = 0; i < 4; i++) { xdr_double(&xdrs, &data); printf("%g\n", data); } </code></pre> <p>You can encode and decode complex structures using XDR. This was a very dumb way of sending four doubles to a file, and generally you should instead use xdr_array() to read/write arrays of some data type. The same commands, in the same order, have to be executed when saving and when loading the file. In fact, you can use <a href="http://linux.die.net/man/1/rpcgen" rel="nofollow noreferrer">rpcgen</a> to generate C structs and their corresponding xdr functions automatically.</p>

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