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我试图在 matlab 中读取一个浮点数组，存储在二进制文件中。最初文件是通过内存映射技巧在 C++ 代码中创建的。

C++ 代码：

#include <iostream>
#include <sys/types.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
int main() 
{
    const char* filePath   = "test_file.dat";
    const size_t NUM_ELEMS = 11;

    /* Write the float array to the binary file via memory mapping */
    const size_t NUM_BYTES = NUM_ELEMS * sizeof(float);//array of the 11 floats;    
    int fd = open(filePath, O_RDWR | O_CREAT | O_TRUNC, 0);//open file
    lseek (fd, NUM_BYTES - 1, SEEK_SET);//stretch the file size
    write(fd, "", 1);//write empty string at the end of file
    float* mappedArray = (float*)mmap(0, NUM_BYTES, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);//map array to the file

    for(size_t i = 0; i < NUM_ELEMS; ++i)//fill array
        mappedArray[i] = static_cast<float>(i) / 10.0f;

    munmap(mappedArray, NUM_BYTES);
    close(fd);

    /* Test reading the recorded file*/    
    std::ifstream fl(filePath, std::ios::in | std::ios::binary);
    float data = 0.0f;
    for(size_t i = 0; i < NUM_ELEMS; ++i)
    {
        fl.read(reinterpret_cast<char*>(&data), sizeof(data)); 
        std::cout<<data<<"\n";
    }

    fl.close();
}

从 C++ 代码中测试读取文件显示正确的结果 - 文件已成功记录。从 C++ 读取的结果：

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

但是，尝试从 matlab 读取此文件会产生错误（数据不正确）：

Matlab代码：

function out = readDataFromFile()
    fid = fopen('test_file.dat','r','b'); 
    out = fread(fid, 11, '*float');  
    fclose(fid);
end

从matlab读取的结果：

0 -429492128 -428443584 -6,3526893e-23 -429492160 8,8281803e-44 -6,3320104e-23 4,1723293e-08 -428443616 2,7200760e+23 4,6006030e-41

我想指出，如果我编写 uint8_t（或 unsigned char）数组，则从 matlab 读取此文件成功。我在matlab中做错了什么？

我的系统- 64 位 Ubuntu 13.04，c++ 编译器- gcc 4.8，matlab - 2013a

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1 回答 1

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问题通过更换解决

fid = fopen('test_file.dat','r','b');

在

fid = fopen('test_file.dat','r');
于 2013-10-07T21:06:36.983 回答