On Mon, Oct 23, 2017 at 9:18 AM, Ruslan R. Laishev <zator@yandex.ru> wrote:

 The question was "How To?". :-)
 I looking for something like follows:
 ...
 char __data_bytea[128];


 RAND_bytes(__data_bytea, sizeof(__data_byte));
 ...
 argv[0] = __data_bytea;
 argl[0] = sizeof(__data_bytea);

 ...
 PQexecPrepared ( ... argv, argl , ...);

check out libpqtypes -- it does exactly what you want.

merlin