linux read

[简书成研]

4 79 ef ab 2 0 0 0 4 0 0 0 41 1f 14 fe
engine: 0 speed: 0 time: 5374
4 79 ef ab 2 0 0 0 4 0 0 0 41 1f 14 fe
engine: 0 speed: 0 time: 5374
4 79 ef ab 2 0 0 0 4 0 0 0 41 1f 14 ff
engine: 0 speed: 0 time: 5375
4 79 ef ab 2 0 0 0 4 0 0 0 41 1f 15 0
engine: 0 speed: 0 time: 336

4 79 ef ab 2 0 0 0 4 0 0 0 41 1f 15 00
这个地方在read的时候，末尾的0少读取了一个， 但是是发送了的，如何解决？

[赵4老师]

The following example reads data from the file associated with the file descriptor fd into the buffer pointed to by buf. #include <sys/types.h> #include <unistd.h> ... char buf[20]; size_t nbytes; ssize_t bytes_read; int fd; ... nbytes = sizeof(buf); bytes_read = read(fd, buf, nbytes); ...

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);
    }
}