Is there any ways to pass an array as parameter in libpq?

Hello,

I'm starting to learn programming with libpq.
In the main loop of my code, I will receive some data in the format of an array of a struct. The data will be inserted to the database, in different lines.
I also need to update the last record in the table before the insertion. So I plan to write a pl/pgsql function (procedure) to perform the whole updating and inserting.
But I don't know how to pass the array to the procedure through libpq. It seems the only way is to using libpq to do updating and inserting separately. Like this

for(;;) {
/* receive data */

/* libpq updating */
PQexec(...);

PQprepare(...);
for (i=0; i<n; i++) {
/* libpq inserting */
PQexecPrepared()...
}
}

The PQprepare function has to be called in each loop.So my question is that whether there is a method to pass the array as parameter to libpq?

Best regards,
Xun

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