---
title: "W7500P, fopen(), retarget.c"
url: "https://maker.wiznet.io/forum/13773"
markdown_url: "https://maker.wiznet.io/forum/13773/md"
type: "Forum topic"
category: "MCU & Boards"
author: "Yongjin Jang"
created: "2020-04-07T01:09:56+09:00"
last_activity: "2020-04-07T01:09:56+09:00"
language: "en"
views: 723
replies: 0
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# W7500P, fopen(), retarget.c

## Question

Asked by Yongjin Jang on 2020-04-07 in MCU & Boards.

안녕하세요,
W7500P를 Keil 환경에서 개발하고 있습니다.

Wiznet에서 제공된 Keil, SSP 어플리케이션에서(다른 예도 마찬가지이지만) retarget.c를 같이 사용하며 fopen()을 사용하면

fp = fopen(“/sd/mydir/sdtest.txt”, “w”);

```
if(fp == NULL)
{
    //error("Could not open file for write\n");
}
fprintf(fp, "Hello fun SD Card World!");
fclose(fp);
```

=>
.\Objects\BX6416R10_W7500P_R100_20200217.axf: Error: L6200E: Symbol __stdout multiply defined (by stdio_streams.o and retarget.o).
.\Objects\BX6416R10_W7500P_R100_20200217.axf: Error: L6200E: Symbol __stdin multiply defined (by stdio_streams.o and retarget.o).

이런 메세지가 발생합니다.

---

Source: https://maker.wiznet.io/forum/13773