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    char str_var[20];
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    EXEC SQL BEGIN DECLARE SECTION;
         char str_var_h[20];
    EXEC SQL END   DECLARE SECTION;
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    char str_var[20];
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    EXEC SQL BEGIN DECLARE SECTION;
         char str_var_h[20];
    EXEC SQL END   DECLARE SECTION;
    void  c_var_to_host();
    void  host_var_to_c();
    /* I call this functions when needed. The C and Host
    variables always will be with the same value */
    void c_var_to_host()
    {  strcpy(str_var_h, str_var);    }
    void host_var_to_c()
    {  strcpy(str_var, str_var_h);    }
...