Using codegen for reading data from a text file in C

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Yuval Geyari 2018-9-2

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https://ww2.mathworks.cn/matlabcentral/answers/417184-using-codegen-for-reading-data-from-a-text-file-in-c

编辑： Kevin Chng 2018-9-3

I'm trying to write a code that reads numeric data from a text file and stores it in an array. Eventually, the code should be compiled as an '.exe' file using codegen. The problem is that C programming does not support "obvious" functions that can help me do it, such as fgets or str2num. Can anyone help me write a Matlab code that can eventually be compiled? The format of the data text file is mine to decide.

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Walter Roberson 2018-9-3

Kevin, that is more like int2str. It does not handle negative numbers, and I suspect that it outputs an extra 0 when the value is not an integer.

The poster needs to read in numbers, not output them.

Kevin Chng 2018-9-3

编辑：Kevin Chng 2018-9-3

Okay, just realised that I see his question wrongly.

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Answer 1

Yuval Geyari 2018-9-3

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Thanks everyone, I solved the issue by using the functions strtok and str2double, which are supported by C programming.

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Answer 2

Walter Roberson 2018-9-3

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https://www.mathworks.com/help/simulink/slref/coder.ceval.html

You should almost certainly be able to use anything in the standard C library, including sscanf, if you invoke it by coder.ceval or coder.extrinsic.

Now, there is the issue that the standard C library has no file system support. fgets is not truly part of C: it is an operating system function such as might be defined by POSIX.

This basically means that if you are writing a C program for deployment running a literal toaster, that it is not at all an error that the compiler does not permit you to access files. Or more modernly, it is not at all an error that your arduino does not support files. Raspberry Pi is a hosted implementation and does support files, but that is outside of C proper.