rem: if ( !operation )
add: if ( !operation || ! TREE_VIEW_LISTE_OPERATIONS)
context: GtkTreeIter *cherche_iter_operation ( struct structure_operation *operation ){    struct structure_operation *operation_tmp;    GtkTreeIter iter;    if ( !operation )	return NULL;    /*     si l'est la ligne blanche qui est demandée (ope=-1), p_tab doit être fixé avant... */    if ( operation != GINT_TO_POINTER (-1))	p_tab_nom_de_compte_variable = p_tab_nom_de_compte + operation -> no_compte;    else	verification_p_tab ("cherche_iter_operation");    /*     on va faire le tour de la liste, et dès qu'une opé = operation */    /* 	on retourne son iter */    gtk_tree_model_get_iter_first ( GTK_TREE_MODEL ( gtk_tree_view_get_model ( GTK_TREE_VIEW ( TREE_VIEW_LISTE_OPERATIONS ))),				    &iter );    operation_tmp = NULL;    do    {	gtk_tree_model_get ( GTK_TREE_MODEL ( gtk_tree_view_get_model ( GTK_TREE_VIEW ( TREE_VIEW_LISTE_OPERATIONS ))),			     &iter,			     9, &operation_tmp,			     -1 );    }    while ( operation_tmp != operation	    &&	    gtk_tree_model_iter_next ( GTK_TREE_MODEL ( gtk_tree_view_get_model ( GTK_TREE_VIEW ( TREE_VIEW_LISTE_OPERATIONS ))),				       &iter ));    if ( operation_tmp == operation )	return ( gtk_tree_iter_copy ( &iter ));    else	return NULL;}