How to solve segmentation violation error when I call a C-MEX function which is compiled correctly?

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Hi;
I have compiled a C-mex file in matlab successfully. But, when I try to call it in a matlab program, "Segmentation violation" error appears and Matlab is forced to close. The error which I get is:
------------------------------------------------------------------------
Segmentation violation detected at Wed Apr 27 16:51:04 2015
------------------------------------------------------------------------
Configuration:
Crash Decoding : Disabled
Crash Mode : continue (default)
Current Graphics Driver: Unknown hardware
Current Visual : 0x23 (class 4, depth 24)
Default Encoding : UTF-8
GNU C Library : 2.19 stable
Host Name : iampc25
MATLAB Architecture : glnxa64
MATLAB Root : /opt/MATLAB/R2015a
MATLAB Version : 8.5.0.197613 (R2015a)
OpenGL : hardware
Operating System : Linux 3.19.0-32-generic #37~14.04.1-Ubuntu SMP x86_64
Processor ID : x86 Family 6 Model 60 Stepping 3, GenuineIntel
Virtual Machine : Java 1.7.0_60-b19 with Oracle Corporation Java HotSpot(TM) 64-Bit Server VM mixed mode
Window System : The X.Org Foundation (11701000), display :0
Fault Count: 1
Abnormal termination:
Segmentation violation
Register State (from fault):
RAX = 00007f94bdadd7f0 RBX = 0000000000000001
RCX = 00007f95d6d0c320 RDX = 00007f95e3ede870
RSP = 00007f95e3ede520 RBP = 00007f95e3ede8b0
RSI = 00007f95d6d0c358 RDI = 0000000000000008
R8 = 000bf5f8000000c0 R9 = 0000000000000008
R10 = 0003fca800000040 R11 = 0003fca800000040
R12 = 000bf5f8000000c0 R13 = 00007f95e3ede870
R14 = 00007f95d6d0c320 R15 = 00007f95e3ede870
RIP = 00007f94bdaddeda EFL = 0000000000010202
CS = 0033 FS = 0000 GS = 0000
Stack Trace (from fault):
[ 0] 0x00007f94bdaddeda /opt/MATLAB/R2015a/bin/glnxa64/mkl.so+15728346
[ 1] 0x0000000000000000 <unknown-module>+00000000
This error was detected while a MEX-file was running. If the MEX-file
is not an official MathWorks function, please examine its source code
for errors. Please consult the External Interfaces Guide for information
on debugging MEX-files.
any help is appreciated !!
  4 Comments
Walter Roberson
Walter Roberson on 28 Apr 2016
MATLAB imposes its own dynamic library path. Compare the DYLD_LIBRARY_PATH environment variable outside of MATLAB with the one inside MATLAB. In particular for your situation pay attention to where mkl.so is being found. You may wish to use ldd to see where it need to load it from.

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Answers (1)

Alessandro Masullo
Alessandro Masullo on 28 Apr 2016
I suggest you to run a debugger on your C file. I've never done it on GNU/Linux, but it should be possible in the same way as on Windows.
Simply open your debugger, attach it to the process of Matlab, compile your mex file with "-g", set a debug point in your mex routine, run it from matlab and execute your C file line by line. When Matlab crashes, you can see exactly where your C file is generating the error.
Hope it helps.

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