public static extern int querysmstatusa(
uint sm_id,
char orgton,
char orgnpi,
string orgaddr,
char[] destton,
char[] destnpi,
string destaddr,
string final_date,
out uint sm_status,
out uint error_code);
......
char[] destton={'0'};
char[] destnpi={'0'};
string final_date="";
string destaddr="";
uint sm_status,error_code;

int i=querysmstatusa(sm_id,'2','1',"999999",destton,destnpi, destaddr,final_date,out sm_status, out error_code);

i,sm_status,error_code 能返回正确的值.