MATLAB: File path containing %

environment-variablesfileMATLAB

I would like to get the path for directories containing % (like %MATLAB_ROOT%, %APPDATA%, etc.) in Windows. However, functions like fileparts cannot interpret the percent sign. Is there a way to make this possible within MATLAB, or the only solution is to call system commands?

Thanks, Zoli

Best Answer

Use getenv, Environment variable to get values of environment variables of the underlying operating system, e.g.

>> getenv('OS')
ans =
Windows_NT
>> getenv('APPDATA')
ans =
C:\Users\poi\AppData\Roaming

%NAME% gets the value of NAME in the Command Prompt, e.g.

Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.
C:\Users\poi>echo %APPDATA%
C:\Users\poi\AppData\Roaming
C:\Users\poi>

And there is the Matlab function, matlabroot

>> matlabroot
ans =
C:\Program Files\MATLAB\R2013b

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MATLAB: Does setenv not set variables for MEX functions

Hi,

I think the following Microsoft statement should help here:

"getenv and _putenv use the copy of the environment pointed to by the global variable _environ to access the environment. getenv operates only on the data structures accessible to the run-time library and not on the environment "segment" created for the process by the operating system. "

http://msdn.microsoft.com/en-us/library/tehxacec(v=vs.80).aspx

I think you would need to use GetEnvironmentVariable instead

http://msdn.microsoft.com/en-us/library/windows/desktop/ms683188%28v=vs.85%29.aspx

To answer it pretty short: It seems like getenv only looks at the global variables, and GetEnvironmentVariable works for application specific too

I modified the code to (change extension to .cpp)

#include <mex.h>
#include "Windows.h"
void mexFunction(int nargout, mxArray *pargout [ ], int nargin, const mxArray *pargin[])
{
    const DWORD buff_size = 50;
    LPTSTR buff = new TCHAR[buff_size];
    DWORD var_size;
    buff[0] = '\0';
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    printf("AAA %s\n", getenv("AAA"));
    var_size = GetEnvironmentVariable("AAA",buff,buff_size);
    printf("AAA through GetEnvironmentVariable %s\n",buff);
}

And when you run it you see this:

>> test
OS  Windows_NT
AAA (null)
AAA through GetEnvironmentVariable 
>> setenv('AAA','BBB11')
>> test
OS  Windows_NT
AAA (null)
AAA through GetEnvironmentVariable BBB11
>>

MATLAB: Do I get a libc.so.6: not found error when launching MATLAB in Ubuntu

To resolve this problem, open a Terminal window and use the commands below depending on your OS architecture:

For 64-bit Ubuntu:

sudo ln -s /lib/x86_64-linux-gnu/libc.so.6 /lib64/libc.so.6

For 32-bit Ubuntu:

sudo ln -s /lib/i386-linux-gnu/libc.so.6 /lib/libc.so.6

For using the Student Version on 64-bit:

sudo ln -s /lib/x86_64-linux-gnu/libc.so.6 /lib

Afterwards try starting MATLAB again.

Best Answer

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