Using mariadb_stmt_execute_direct of queries with parameters simply crashes the application.
The crash occurs in mariadb_stmt_execute_direct call, in line:752 of mariadb_stmt.c
if (indicator == STMT_INDICATOR_NTS ||
(!stmt->row_size && stmt->params[i].length[j] == (unsigned long)-1))

#include <stdio.h>

#include <mysql.h>

#define NUMBER_OF_TEST_LOOPS 10

#ifndef OK

1. define OK 0
   #endif
   #ifndef FAIL
2. define FAIL 1
   #endif
   #ifndef SKIP
3. define SKIP -1
   #endif
   #ifndef FALSE
4. define FALSE 0
   #endif
   #ifndef TRUE
5. define TRUE 1
   #endif

#define check_stmt_rc(rc, stmt) \
if (rc)\
{\
diag("Error: %s (%s: %d)", mysql_stmt_error(stmt), _FILE, __LINE_);\
return(FAIL);\
}

#define check_mysql_rc(rc, mysql) \
if (rc)\
{\
diag("Error (%d): %s (%d) in %s line %d", rc, mysql_error(mysql), \
mysql_errno(mysql), _FILE, __LINE_);\
return(FAIL);\
}

void diag(char const *fmt, ...);
int main(int argc, char *argv)
{
MYSQL *ma;
MYSQL_STMT *stmt;
MYSQL_BIND bind[2];
unsigned long length[2];
my_bool is_null[2], error[2];
int i, id, param_count= 1;

ma = mysql_init(NULL);
if (!mysql_real_connect(ma, "localhost", "root", "root", "test", 3308, NULL, 0))

else

stmt = mysql_stmt_init(ma);

memset(bind, '\0', sizeof(bind));
memset(is_null, '\0', sizeof(is_null));
memset(length, '\0', sizeof(length));
memset(error, '\0', sizeof(error));

bind[0].buffer_type = MYSQL_TYPE_LONG;
bind[0].buffer = (void *)&id;
bind[0].buffer_length = 4;
bind[0].is_null = &is_null[0];
bind[0].length = &length[0];
bind[0].error = &error[0];

mysql_stmt_attr_set(stmt, STMT_ATTR_PREBIND_PARAMS, &param_count);
check_stmt_rc(mysql_stmt_bind_param(stmt, bind), stmt);
check_stmt_rc(mariadb_stmt_execute_direct(stmt, "SELECT ?", strlen("SELECT ?")), stmt);
check_stmt_rc(mysql_stmt_store_result(stmt), stmt);
check_stmt_rc(mysql_stmt_free_result(stmt), stmt);

mysql_stmt_close(stmt);
mysql_close(ma);

exit(0);
}