Wrong values after reading back data with fread in C

Question

I am using tmpfile() to create a file (so it's automatically opened in binary mode).
Then I write some floats in it with fwrite(). All these floats are > 0.

The problem is that when I try to read these values (that are >0) back with fread(), I get negative values!

The values I write are out[i][j][couche] which are OK (it is impossible for them to be <0 because of their definition). The problem is at the end (fread).

void flou_bis (FILE * fp, PIXRVB **out, PIXRVB **in, int np, int nl, int rayon, int couche){
    int i,j,k,l,nb;
    float ret1, ret2;
    float rCouche;

    /* Other things not relevant..
    (process the values of array out[][][] ...)*/

    for (i=0; i<nl; i++)
    {
        for (j=0; j<np; j++)
        {
            fwrite ( &(out[i][j][couche]) , sizeof(float), 1, fp);
        }
    }

    rewind(fp);
    /*fsync(fp); // Useless
    rewind(fp);*/

    printf("%d float read\n", fread ( &ret2, sizeof(float), 1, fp)); /*Here is the problem!!! */
    printf("%f\n", ret2);
}

Answer 1

Problem solved, I needed to create a temp variable to force the cast:

float ent = (float) out[i][j][couche];
fwrite ( &ent, sizeof(float), 1, fp);

without the (float) it doesn't work, I have no idea why Thank you all for helping ;)