stderr を使ってみる (C++)

C++

Published: 2020-03-22

確認環境

$ g++ --version
g++ (Homebrew GCC 9.2.0) 9.2.0
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

調査

test.cpp

#include <bits/stdc++.h>
using namespace std;

int main() {
    fprintf(stderr, "message: %s\n", "error happended");
}

出力結果

message: error happended

fprintf で出力先を stderr にして使います。

stderr can be used as an argument for any function that takes an argument of type FILE* expecting an output stream, like fputs or fprintf.

参考

stderr - C++ Reference