我正在尝试在matlab中读取存储在二进制文件中的浮点数组。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阅读的结果:
0 -429492128 -428443584 -6,3526893e-23 -429492160 8,8281803e-44 -6,3320104e-23 4,1723293e-08 -428443616 2,7200760e + 23 4,6006030e-41
我想注意,如果我编写uint8_t(或unsigned char)数组,从matlab读取此文件会成功。 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
答案 0 :(得分:0)
通过替换
解决了这个问题fid = fopen('test_file.dat','r','b');
在
fid = fopen('test_file.dat','r');