user-0 提问: Linux下关于文件操作出现乱码的问题

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user: user-1
content: 对电脑而言没有乱码，只有二进制字节；对人脑才有乱码。啊 GBK:0xB0 0xA1,Unicode-16 LE:0x4A 0x55,Unicode-16 BE:0x55 0x4A,UTF-8:0xE5 0x95 0x8A void HexDump(char *buf,int len,int addr) {     int i,j,k;     char binstr[80];      for (i=0;i<len;i++) {         if (0==(i%16)) {             sprintf(binstr,"%08x -",i+addr);             sprintf(binstr,"%s %02x",binstr,(unsigned char)buf[i]);         } else if (15==(i%16)) {             sprintf(binstr,"%s %02x",binstr,(unsigned char)buf[i]);             sprintf(binstr,"%s  ",binstr);             for (j=i-15;j<=i;j++) {                 sprintf(binstr,"%s%c",binstr,('!'<buf[j]&&buf[j]<='~')?buf[j]:'.');             }             printf("%s\n",binstr);         } else {             sprintf(binstr,"%s %02x",binstr,(unsigned char)buf[i]);         }     }     if (0!=(i%16)) {         k=16-(i%16);         for (j=0;j<k;j++) {             sprintf(binstr,"%s   ",binstr);         }         sprintf(binstr,"%s  ",binstr);         k=16-k;         for (j=i-k;j<i;j++) {             sprintf(binstr,"%s%c",binstr,('!'<buf[j]&&buf[j]<='~')?buf[j]:'.');         }         printf("%s\n",binstr);     } }  //iconv_linux下字符集编码转换轻松实现 (1) iconv_t iconv_open(const char *tocode, const char *fromcode); //此函数说明将要进行哪两种编码的转换,tocode是目标编码,fromcode是原编码,该函数返回一个转换句柄,供以下两个函数使用。 (2) size_t iconv(iconv_t cd,char **inbuf,size_t *inbytesleft,char **outbuf,size_t *outbytesleft); //此函数从inbuf中读取字符,转换后输出到outbuf中,inbytesleft用以记录还未转换的字符数,outbytesleft用以记录输出缓冲的剩余空间。 (3) int iconv_close(iconv_t cd); //此函数用于关闭转换句柄,释放资源。  //例子1: 用C语言实现的转换示例程序  /* f.c : 代码转换示例C程序 */ #include <iconv.h> #define OUTLEN 255 main() { char *in_utf8 = "姝ｅ?ㄥ??瑁?"; char *in_gb2312 = "正在安装"; char out[OUTLEN];  /*unicode码转为gb2312码*/ rc = u2g(in_utf8,strlen(in_utf8),out,OUTLEN); printf("unicode-->gb2312 out=%sn",out); //gb2312码转为unicode码  rc = g2u(in_gb2312,strlen(in_gb2312),out,OUTLEN); printf("gb2312-->unicode out=%sn",out); } /*代码转换:从一种编码转为另一种编码*/ int code_convert(char *from_charset,char *to_charset,char *inbuf,int inlen,char *outbuf,int outlen) { iconv_t cd; int rc; char **pin = &inbuf; char **pout = &outbuf;  cd = iconv_open(to_charset,from_charset); if (cd==0) return -1; memset(outbuf,0,outlen); if (iconv(cd,pin,&inlen,pout,&outlen)==-1) return -1; iconv_close(cd); return 0; } /*UNICODE码转为GB2312码*/ int u2g(char *inbuf,int inlen,char *outbuf,int outlen) { return code_convert("utf-8","gb2312",inbuf,inlen,outbuf,outlen); } /*GB2312码转为UNICODE码*/ int g2u(char *inbuf,size_t inlen,char *outbuf,size_t outlen) { return code_convert("gb2312","utf-8",inbuf,inlen,outbuf,outlen); }  //例子2: 用C++语言实现的转换示例程序  /* f.cpp : 代码转换示例C++程序 */ #include <iconv.h> #include <iostream>  #define OUTLEN 255  using namespace std;  // 代码转换操作类  class CodeConverter {  private: iconv_t cd; public:  // 构造 CodeConverter(const char *from_charset,const char *to_charset) { cd = iconv_open(to_charset,from_charset); }   // 析构 ~CodeConverter() { iconv_close(cd); }   // 转换输出 int convert(char *inbuf,int inlen,char *outbuf,int outlen) { char **pin = &inbuf; char **pout = &outbuf;  memset(outbuf,0,outlen); return iconv(cd,pin,(size_t *)&inlen,pout,(size_t *)&outlen); } };  int main(int argc, char **argv) { char *in_utf8 = "姝ｅ?ㄥ??瑁?"; char *in_gb2312 = "正在安装"; char out[OUTLEN];  // utf-8-->gb2312 CodeConverter cc = CodeConverter("utf-8","gb2312"); cc.convert(in_utf8,strlen(in_utf8),out,OUTLEN); cout << "utf-8-->gb2312 in=" << in_utf8 << ",out=" << out << endl;  // gb2312-->utf-8 CodeConverter cc2 = CodeConverter("gb2312","utf-8"); cc2.convert(in_gb2312,strlen(in_gb2312),out,OUTLEN); cout << "gb2312-->utf-8 in=" << in_gb2312 << ",out=" << out << endl; }    二、利用iconv命令进行编码转换  iconv命令用于转换指定文件的编码,默认输出到标准输出设备,亦可指定输出文件。  用法： iconv [选项...] [文件...]  有如下选项可用:  输入/输出格式规范： -f, --from-code=名称 原始文本编码 -t, --to-code=名称 输出编码  信息： -l, --list 列举所有已知的字符集  输出控制： -c 从输出中忽略无效的字符 -o, --output=FILE 输出文件 -s, --silent 关闭警告 --verbose 打印进度信息  -?, --help 给出该系统求助列表 --usage 给出简要的用法信息 -V, --version 打印程序版本号  例子: iconv -f utf-8 -t gb2312 aaa.txt >bbb.txt 这个命令读取aaa.txt文件，从utf-8编码转换为gb2312编码,其输出定向到bbb.txt文件。  小结: Linux为我们提供了强大的编码转换工具,给我们带来了方便。

user: user-0
content: 抱歉，图片传不上去，大概是出现了一个类似问号?的乱码

user: user-0

user: user-2
content: #include <sys/types.h> #include <sys/stat.h> #include <stdio.h> #include <string.h> #include <stdlib.h> #include <errno.h> #include <unistd.h> #include <fcntl.h> #include <pthread.h> #include <semaphore.h>  #define infile "infile.dat" #define outfile "outfile.dat"  sem_t f1; sem_t f2;  void inputdata() {     int infd;     char buf[50];      if ((infd = open(infile, O_WRONLY | O_TRUNC | O_CREAT, 10700)) == -1)     {         printf("ERROR, OPEN READ FILE FAILED:%s \n", sys_errlist[errno]);         //printf("ERROR, OPEN READ FILE FAILED:%s \n", strerror(errno));         exit(255);     }      printf("Please enter the data:\n");     printf("(Ctrl+D ---- quit)\n");      while(fgets(buf, sizeof(buf), stdin))     {         if (write(infd, buf, strlen(buf)) != strlen(buf)) {             printf("ERROR, WRITE FILE FAILED:%s \n", sys_errlist[errno]);             //printf("ERROR, WRITE FILE FAILED:%s \n", strerror(errno));             exit(255);         }     }     close(infd);      sem_post(&f1); }  void copydata() {     sem_wait(&f1);      int infd, outfd;     char buf[50];      if ((infd = open(infile, O_RDONLY))==-1)     {         printf("ERROR, OPEN READ FILE FAILED:%s \n", sys_errlist[errno]);         //printf("ERROR, OPEN READ FILE FAILED:%s \n", strerror(errno));         exit(255);     }      if ((outfd = open(outfile, O_WRONLY | O_TRUNC | O_CREAT, 10700))==-1)     {         printf("ERROR, OPEN WRITE FILE FAILED:%s \n", sys_errlist[errno]);         //printf("ERROR, OPEN WRITE FILE FAILED:%s \n", strerror(errno));         exit(255);     }      int count;      while((count = read(infd, buf, sizeof(buf))) > 0)     {         if (count != write(outfd, buf, count))         {             printf("ERROR, WRITE FILE FAILED:%s \n", sys_errlist[errno]);             //printf("ERROR, WRITE FILE FAILED:%s \n", strerror(errno));             exit(255);         }     }      close(infd);     close(outfd);      sem_post(&f2); }   void showdata() {     sem_wait(&f2);      int outfd;     char buf[50];      if ((outfd = open(outfile, O_RDONLY, 10700))==-1)     {         printf("ERROR, OPEN WRITE FILE FAILED:%s \n", sys_errlist[errno]);         //printf("ERROR, OPEN WRITE FILE FAILED:%s \n", strerror(errno));         exit(255);     }      int count;      printf("\nThe data in the file:\n");      memset(buf, 0, sizeof(buf));    /*初始化缓存为0*/     while((count = read(outfd, buf, sizeof(buf) - 1)) > 0)    /*防止读到的数据是50个字符，最后一个字符用于字符串结束标记 '\0' */     {         printf("count = %d\n", count);         printf("%s", buf);         memset(buf, 0, sizeof(buf));    /*初始化缓存为0*/     }      close(outfd); }  int main(void) {     pthread_t t1,t2,t3,t4;     sem_init(&f1,0,0);     sem_init(&f2,0,0);      pthread_create(&t1,NULL, (void *)showdata, NULL);     pthread_create(&t2,NULL, (void *)copydata, NULL);     pthread_create(&t3,NULL, (void *)inputdata, NULL);      pthread_join(t1,NULL);      return 0; } 出现乱码，是字符串没有找到'\0',即字符串结束标记；需要对缓存在读之前做初始化操作（初始化为0， 0 值等于'\0')，另一个方面，若文件中的字符大于缓存长度，所以每次读取都最大读取缓存长度减1。