How to get the localized return string of C++ strerror? - c++

Question

My Minecraft server crushed caused by insufficient spaces. About 2 hours before crushed, there were some plugins printing exception stack traces including java.io.ioexception: 设备上没有空间 (means java.io.IOException: No space left on device). After I restart it, I found that all the buildings players built in the 2 hours disappeared, and no any plugins can restore it (include CoreProtect, because of insufficient spaces, it can not submit database transactions).
In order to close server immediately when there's no enough spaces, I decided to develop a plugin. Because there's no way to listen exceptions thrown by all threads, I implemented this function by listen logs.
Any code print log like java.io.ioexception: ${message} or [...] ... [...]: java.io.ioexception: ${message} will trigger the shutdown of server.
Pay attention to the error message: In some platforms, it's 设备上没有空间; In some others platforms, it's No space left on device... So It's necessary to get the localized version of it firstly.
This error message, comes from Operating System, is strerror(28) (C++ function) in Windows or Linux. So I create a native function to invoke it:
// cn.chuanwise.nessc.errno.ErrorMessage;
public class ErrorMessage {
public native static String of(int errno, Locale locale);
}
#include "localed-error-message-native.h"
#include <locale>
#include <string.h>
JNIEXPORT jstring JNICALL Java_cn_chuanwise_nessc_errno_ErrorMessage_of(JNIEnv* env, jclass clz, jint code, jobject locale) {
// find locale class
const jclass locale_class = env->FindClass("java/util/Locale");
const jmethodID to_string_method = env->GetMethodID(locale_class, "toString", "()Ljava/lang/String;");
const jobject locale_string = env->CallObjectMethod(locale, to_string_method);
const char* locale_name = env->GetStringUTFChars(reinterpret_cast<jstring>(locale_string), nullptr);
// set locale
std::setlocale(LC_ALL, locale_name);
const char* strerr = strerror(static_cast<int>(code));
if (strerr == nullptr) {
return nullptr;
} else {
return env->NewStringUTF(strerr);
}
}
ErrorMessage.of(28, Locale.getDefault()) returns No space left on device in my device, but this code throws java.io.IOException: 设备上没有空间 in my device:
final File file = new File("test");
// ...
try (OutputStream outputStream = new FileOutputStream(file)) {
final byte[] buf = new byte[1024];
while (true) {
outputStream.write(buf);
}
}
How to get the localized return string of strerror?