https://github.com/oracle/odpi/issues/35

number-attr.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <inttypes.h>
#include <dpi.h>

static dpiContext *g_context;

#ifndef ARRAY_SIZE
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
#endif

#define chkerr(func) do { \
    if ((func) < 0) { \
        dpiErrorInfo err; \
        dpiContext_getError(g_context, &err); \
        printf("ERROR at line %d\n  %s\n  %s\n", __LINE__, #func, err.message); \
        exit(1); \
    } \
} while (0)

static const char *env(const char *name, const char *default_value)
{
    const char *value = getenv(name);
    if (value == NULL) {
        value = default_value;
    }
    return value;
}

int main()
{
    const char *username = env("ODPIC_SAMPLES_MAIN_USER", "odpicdemo");
    const char *password = env("ODPIC_SAMPLES_MAIN_PASSWORD", "welcome");
    const char *connectString = env("ODPIC_SAMPLES_CONNECT_STRING", "localhost/orclpdb");
    const char *sqltext = "select ObjectCol from TestObjects where IntCol = 1";
    dpiErrorInfo err;
    dpiConn *conn;
    dpiStmt *stmt;
    uint32_t numQueryColumns;
    uint32_t bufferRowIndex;
    dpiObjectAttr *attrs[7];
    dpiQueryInfo queryInfo;
    int found;
    dpiNativeTypeNum nativeTypeNum;
    dpiData *objColValue, attrValue;

    if (dpiContext_create(DPI_MAJOR_VERSION, DPI_MINOR_VERSION, &g_context, &err) < 0) {
        printf("ERROR\n  dpiContext_create()\n %s\n", err.message);
        exit(1);
    }

    chkerr(dpiConn_create(g_context, username, strlen(username), password, strlen(password),
                           connectString, strlen(connectString), NULL, NULL, &conn));
    chkerr(dpiConn_prepareStmt(conn, 0, sqltext, strlen(sqltext), NULL, 0, &stmt));
    chkerr(dpiStmt_execute(stmt, 0, &numQueryColumns));
    chkerr(dpiStmt_fetch(stmt, &found, &bufferRowIndex));
    if (!found) {
        printf("No rows are found.\n");
        exit(1);
    }
    chkerr(dpiStmt_getQueryValue(stmt, 1, &nativeTypeNum, &objColValue));
    chkerr(dpiStmt_getQueryInfo(stmt, 1, &queryInfo));
    chkerr(dpiObjectType_getAttributes(queryInfo.typeInfo.objectType, ARRAY_SIZE(attrs), attrs));

    printf("Getting ObjectCol.NumberValue as DPI_NATIVE_TYPE_DOUBLE\n");
    chkerr(dpiObject_getAttributeValue(objColValue->value.asObject, attrs[0], DPI_NATIVE_TYPE_DOUBLE, &attrValue));
    printf("  => %g\n", attrValue.value.asDouble);

    printf("Getting ObjectCol.NumberValue as DPI_NATIVE_TYPE_INT64\n");
    if (dpiObject_getAttributeValue(objColValue->value.asObject, attrs[0], DPI_NATIVE_TYPE_INT64, &attrValue) == 0) {
        printf("  => %" PRId64 "\n", attrValue.value.asInt64);
    } else {
        dpiContext_getError(g_context, &err);
        printf("  => ERROR: %s\n", err.message);
    }
    printf("Getting ObjectCol.NumberValue as DPI_NATIVE_TYPE_BYTES\n");
    if (dpiObject_getAttributeValue(objColValue->value.asObject, attrs[0], DPI_NATIVE_TYPE_BYTES, &attrValue) == 0) {
        printf("  => %.*s\n", attrValue.value.asBytes.length, attrValue.value.asBytes.ptr);
    } else {
        dpiContext_getError(g_context, &err);
        printf("  => ERROR: %s\n", err.message);
    }

    chkerr(dpiStmt_release(stmt));
    chkerr(dpiConn_release(conn));
    return 0;
}