可变参数及宽字符输出有关问题，为什么是乱码

2012-04-02

可变参数及宽字符输出问题，为什么是乱码代码如下#include iostream#include cstdio#include cstdarg

可变参数及宽字符输出问题，为什么是乱码
代码如下
#include <iostream>
#include <cstdio>
#include <cstdarg>
#include <string>

void MLog(const wchar_t* log, ...)
{
va_list argList;
va_start(argList, log);
std::wstring logString = log;
logString = std::wstring(L"win: ") + log + std::wstring(L"\\n");
wprintf(logString.c_str(), argList);
va_end(argList);
}

int main()
{
MLog(L"%s,%d",L"HELLO WORLD",3);
}

[解决办法]

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引用:

应该用int vprintf(const char *format, va_list ap); 哦

应该是vwprintf吧，但是为什么不能用wprintf，应该也可以才对

[解决办法]
对电脑而言没有乱码，只有二进制字节；对人脑才有乱码。
仅供参考

C/C++ code

#include <stdio.h>#include <stdlib.h>#include <string.h>#ifdef WIN32    #include <windows.h>    #include <io.h>#else    #include <unistd.h>    #include <sys/time.h>    #include <pthread.h>    #define  CRITICAL_SECTION   pthread_mutex_t    #define  _vsnprintf         vsnprintf#endif//Log{#define MAXLOGSIZE 100000000#define ARRSIZE(x) (sizeof(x)/sizeof(x[0]))#include <time.h>#include <sys/timeb.h>#include <stdarg.h>char logfilename1[]="MyLog1.log";char logfilename2[]="MyLog2.log";char logstr[16000];char datestr[16];char timestr[16];char mss[4];CRITICAL_SECTION cs_log;FILE *flog;#ifdef WIN32void Lock(CRITICAL_SECTION *l) {    EnterCriticalSection(l);}void Unlock(CRITICAL_SECTION *l) {    LeaveCriticalSection(l);}#elsevoid Lock(CRITICAL_SECTION *l) {    pthread_mutex_lock(l);}void Unlock(CRITICAL_SECTION *l) {    pthread_mutex_unlock(l);}#endifvoid LogV(const char *pszFmt,va_list argp) {    struct tm *now;    struct timeb tb;    if (NULL==pszFmt||0==pszFmt[0]) return;    if (-1==_vsnprintf(logstr,ARRSIZE(logstr),pszFmt,argp)) logstr[ARRSIZE(logstr)-1]=0;    ftime(&tb);    now=localtime(&tb.time);    sprintf(datestr,"%04d-%02d-%02d",now->tm_year+1900,now->tm_mon+1,now->tm_mday);    sprintf(timestr,"%02d:%02d:%02d",now->tm_hour     ,now->tm_min  ,now->tm_sec );    sprintf(mss,"%03d",tb.millitm);    printf("%s %s.%s %s",datestr,timestr,mss,logstr);    flog=fopen(logfilename1,"a");    if (NULL!=flog) {        fprintf(flog,"%s %s.%s %s",datestr,timestr,mss,logstr);        if (ftell(flog)>MAXLOGSIZE) {            fclose(flog);            if (rename(logfilename1,logfilename2)) {                remove(logfilename2);                rename(logfilename1,logfilename2);            }            flog=fopen(logfilename1,"a");            if (NULL==flog) return;        }        fclose(flog);    }}void Log(const char *pszFmt,...) {    va_list argp;    Lock(&cs_log);    va_start(argp,pszFmt);    LogV(pszFmt,argp);    va_end(argp);    Unlock(&cs_log);}//Log}int main(int argc,char * argv[]) {    int i;#ifdef WIN32    InitializeCriticalSection(&cs_log);#else    pthread_mutex_init(&cs_log,NULL);#endif    for (i=0;i<10000;i++) {        Log("This is a Log %04d from FILE:%s LINE:%d\n",i, __FILE__, __LINE__);    }#ifdef WIN32    DeleteCriticalSection(&cs_log);#else    pthread_mutex_destroy(&cs_log);#endif    return 0;}
[解决办法]
MLog函数写法有点问题，正确写法：

void MLog(const wchar_t* log, ...)
{
va_list argList;
va_start(argList, log);
WCHAR wBuffer[1024];
memset(wBuffer,0,sizeof(wBuffer));
_snwprintf( wBuffer, sizeof(wBuffer)/sizeof(WCHAR),log, argList);//把可变参数格式化输出到buffer
std::wstring logString = wBuffer;//关键是这行的问题 
 
logString = std::wstring(L"win: ") + log + std::wstring(L"\\n");
wprintf(logString.c_str(), argList);
va_end(argList);
}

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