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POSaving a C struct with a char* string into a file
 

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    <p>I'm trying to save a struct with a char* string into a file. </p> <pre><code>struct d_object { int flags; int time; int offset; char *filename; }; </code></pre> <p>The problem is that when doing that I will obviously only save the address of that pointer rather than the string. So what I've done is simply use a character array and but I'm forced to set the maximum size of the string. This works fine, however I was wondering if there is anyway of storing the struct with a char* (that I malloc at some point) in a file and then retrieve it. I can save the string and the struct separate and then retrieve them but it's quite a mess. It would be preferable if I could load and save the entire struct (the one above) into the file. Thanks!</p> <p>The code with the char array is below:</p> <pre><code>#include &lt;stdio.h&gt; #include &lt;string.h&gt; #include &lt;fcntl.h&gt; struct d_object { int flags; int time; int offset; char filename[255]; }; int main(int argc, char **argv) { struct d_object fcb; fcb.flags=5; fcb.time=100000; fcb.offset=220; strncpy(fcb.filename,"myfile",255); int fd=open("testfile",O_RDWR); write(fd,&amp;fcb,sizeof(fcb)); close(fd); int fd2 = open("testfile",O_RDONLY); struct d_object new_fcb; read(fd2,&amp;new_fcb,sizeof(new_fcb)); printf("read from file testfile: %s\n",new_fcb.filename); return 0; } </code></pre> <p>P.S.: I'm not using the STREAM functions simply because this is actually meant to be run on an embedded OS that doesn't have them. I've just adapted the code for *BSD/Linux so it makes more sense when asking the question.</p>
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    1. COThe way you're using fread is very wrong. You don't declare a char buffer and read into it, then point a struct pointer at it. Simply declare a struct and pass the pointer to that struct to fread. The way you've done it is not valid C and is likely to crash on RISC architectures with strict alignment requirements.
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    2. COok, thanks for that. However that's not the main issue at the moment.
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