struct TwoInts {
    uint32_t int1;
    uint32_t int2;
};

CREATE TABLE ints (
   id int,
   field bytea
);

char query[100];
struct TwoInts a = {44, 55};
sprintf(query, "INSERT INTO ints (id, field) VALUES(0, decode('%08X%08X', 'hex'))", a.int1, a.int2);

INSERT INTO ints (id, field) VALUES(0, decode('000000210000002C', 'hex'));

struct TwoInts {
    uint32_t int1;
    uint32_t int2;
};

CREATE TABLE ints (
   id int,
   int1 int,
   int2 int
);

char query[100];
struct TwoInts a = {44, 55};
sprintf(query, "INSERT INTO ints (id, int1, int2) VALUES(0, %d, %d);", int1, int2);

INSERT INTO ints (id, int1, int2) VALUES(0, 44, 55);