调用SQLDirverConnect远程连接oracle的C代码

以下是一个使用SQLDriverConnect远程连接Oracle的C代码示例：

#include <stdio.h>
#include <sql.h>
#include <sqlext.h>

int main() {
    SQLHENV env;
    SQLHDBC dbc;
    SQLHSTMT stmt;
    SQLRETURN ret; 
    SQLCHAR* conn_str = (SQLCHAR*)"DRIVER={Oracle ODBC Driver};SERVER=your_server_address;PORT=1521;UID=your_username;PWD=your_password;DBQ=your_database_name;";

    // Allocate an environment handle
    ret = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &env);
    if (ret != SQL_SUCCESS && ret != SQL_SUCCESS_WITH_INFO) {
        printf("Failed to allocate environment handle\n");
        return -1;
    }

    // Set the ODBC version environment attribute
    ret = SQLSetEnvAttr(env, SQL_ATTR_ODBC_VERSION, (SQLPOINTER)SQL_OV_ODBC3, 0);
    if (ret != SQL_SUCCESS && ret != SQL_SUCCESS_WITH_INFO) {
        printf("Failed to set environment attribute\n");
        return -1;
    }

    // Allocate a connection handle
    ret = SQLAllocHandle(SQL_HANDLE_DBC, env, &dbc);
    if (ret != SQL_SUCCESS && ret != SQL_SUCCESS_WITH_INFO) {
        printf("Failed to allocate connection handle\n");
        return -1;
    }

    // Connect to the database
    ret = SQLDriverConnect(dbc, NULL, conn_str, SQL_NTS, NULL, 0, NULL, SQL_DRIVER_COMPLETE);
    if (ret != SQL_SUCCESS && ret != SQL_SUCCESS_WITH_INFO) {
        printf("Failed to connect to database\n");
        return -1;
    }

    // Allocate a statement handle
    ret = SQLAllocHandle(SQL_HANDLE_STMT, dbc, &stmt);
    if (ret != SQL_SUCCESS && ret != SQL_SUCCESS_WITH_INFO) {
        printf("Failed to allocate statement handle\n");
        return -1;
    }

    // Execute a query
    ret = SQLExecDirect(stmt, (SQLCHAR*)"SELECT * FROM your_table", SQL_NTS);
    if (ret != SQL_SUCCESS && ret != SQL_SUCCESS_WITH_INFO) {
        printf("Failed to execute query\n");
        return -1;
    }

    // Fetch results
    SQLLEN id, name_len;
    SQLCHAR name[256];

    while (SQLFetch(stmt) == SQL_SUCCESS) {
        SQLGetData(stmt, 1, SQL_C_LONG, &id, 0, NULL);
        SQLGetData(stmt, 2, SQL_C_CHAR, name, sizeof(name), &name_len);
        printf("id = %ld, name = %.*s\n", id, name_len, name);
    }

    // Clean up
    SQLFreeHandle(SQL_HANDLE_STMT, stmt);
    SQLDisconnect(dbc);
    SQLFreeHandle(SQL_HANDLE_DBC, dbc);
    SQLFreeHandle(SQL_HANDLE_ENV, env);

    return 0;
}

在此示例中，我们首先分配了一个环境句柄，并设置了ODBC版本环境属性。接下来，我们分配了一个连接句柄，并使用SQLDriverConnect函数连接到Oracle数据库。然后，我们分配了一个语句句柄，并使用SQLExecDirect函数执行一个查询。最后，我们使用SQLGetData函数检索查询结果，并清理句柄。请注意，您需要根据您自己的情况替换连接字符串中的占位符。