我有一个用MATLAB编写的程序，我需要一个计算（代码中的snrf(beta(i),gk_sum,gk_length)），因此C需要发挥作用（通过MEX函数）。在与官方文档和我发现的一些示例进行了反复交流之后，我设法使整个过程工作了几次。但是，现在发生的是，当此计算即将发生时（在函数中），MATLAB崩溃了。 （如果我声明plhs[0]为矩阵-如示例所示-我的输出是一个充满零的矩阵（不正确）。）
这是我的MEX文件中的代码：
#include "mex.h"
#include <math.h>
void snrf(double *beta, double *gk_sum, double *gk_length)
{
double sinr, sinrdb;
sinr = -(*beta)*log(exp(-(*gk_sum)/(*beta)/(*gk_length)));
sinrdb = 10*log10(sinr);
}
/* The gateway function */
void mexFunction(int nlhs, mxArray *plhs[],
int nrhs, const mxArray *prhs[])
{
double *beta;
double *gk_sum;
double *gk_length;
double *output;
if(nrhs != 3) { mexErrMsgTxt("Must have 3 input arguments."); }
if(nlhs != 1) { mexErrMsgTxt("Too many output arguments."); }
beta = mxGetData(prhs[0]);
gk_sum = mxGetData(prhs[1]);
gk_length = mxGetData(prhs[2]);
//plhs[0] = mxCreateDoubleMatrix(1, 1, mxREAL); /*Creates a 1x1 matrix*/
output = mxGetPr(plhs[0]); /* Outuput */
snrf(beta, gk_sum, gk_length);
}
这是崩溃文件：
------------------------------------------------------------------------
Access violation detected at Thu Aug 30 00:35:56 2018
------------------------------------------------------------------------
Configuration:
Crash Decoding : Disabled - No sandbox or build area path
Crash Mode : continue (default)
Current Graphics Driver: Unknown hardware
Default Encoding : windows-1252
Deployed : false
Graphics card 1 : Intel Corporation ( 0x8086 ) Intel(R) HD Graphics 4000 Version 10.18.10.4358 (2015-12-21)
Graphics card 2 : NVIDIA ( 0x10de ) NVIDIA GeForce 610M Version 23.21.13.9135 (2018-3-23)
Host Name : DESKTOP-SMECHLA
MATLAB Architecture : win64
MATLAB Entitlement ID: 6257193
MATLAB Root : C:\Program Files\MATLAB\R2017b
MATLAB Version : 9.3.0.713579 (R2017b)
OpenGL : hardware
Operating System : Microsoft Windows 10 Pro
Processor ID : x86 Family 6 Model 58 Stepping 9, GenuineIntel
Virtual Machine : Java 1.8.0_121-b13 with Oracle Corporation Java HotSpot(TM) 64-Bit Server VM mixed mode
Window System : Version 10.0 (Build 17134)
Fault Count: 1
Abnormal termination:
Access violation
Register State (from fault):
RAX = 000000000000001a RBX = 0000000026749980
RCX = 0000000000000000 RDX = 0000000000000068
RSP = 00000000043f9ec8 RBP = 00000000043f9ef0
RSI = 0000000026748b40 RDI = 0000000026748cc0
R8 = 0000e2d497fd0909 R9 = 00007ffa9e6f0000
R10 = 000000006480b240 R11 = 00000000043f9e70
R12 = 00000000043f9f50 R13 = 000000000000127f
R14 = 00000000c7c70220 R15 = 0000000000000001
RIP = 0000000180089354 EFL = 00010202
CS = 0033 FS = 0053 GS = 002b
Stack Trace (from fault):
[ 0] 0x0000000180089354 bin\win64\pgo\libmx.dll+00562004 mxGetPr+00000000
[ 1] 0x00000000047b15b6 C:\Users\Krazator\Desktop\C_calc\snrf.mexw64+00005558 mexFunction+00000175
[ 2] 0x00000000fc60234a bin\win64\libmex.dll+00140106 mexRunMexFile+00000314
[ 3] 0x00000000fc600d22 bin\win64\libmex.dll+00134434 mexFeature_mexver+00002146
[ 4] 0x00000000fc5ffab7 bin\win64\libmex.dll+00129719 mexUnlock+00028455
[ 5] 0x00000000155dca93 bin\win64\pgo\m_dispatcher.dll+00117395 Mfh_file::dispatch_fh_impl+00000835
[ 6] 0x00000000155dc73e bin\win64\pgo\m_dispatcher.dll+00116542 Mfh_file::dispatch_fh+00000062
[ 7] 0x00000000155ca8d8 bin\win64\pgo\m_dispatcher.dll+00043224 Mfunction_handle::dispatch+00001032
[ 8] 0x0000000016249899 bin\win64\pgo\m_lxe.dll+00235673
[ 9] 0x000000001624b3a6 bin\win64\pgo\m_lxe.dll+00242598
[ 10] 0x000000001624bfb3 bin\win64\pgo\m_lxe.dll+00245683
[ 11] 0x000000001624dff5 bin\win64\pgo\m_lxe.dll+00253941
[ 12] 0x000000001624d44f bin\win64\pgo\m_lxe.dll+00250959
[ 13] 0x000000001624d822 bin\win64\pgo\m_lxe.dll+00251938
[ 14] 0x000000001631331b bin\win64\pgo\m_lxe.dll+01061659 boost::serialization::singleton<boost::archive::detail::pointer_oserializer<boost::archive::binaryTerm_oarchive,MathWorks::lxe::MatlabIrTree> >::get_instance+00604503
[ 15] 0x000000001631ad46 bin\win64\pgo\m_lxe.dll+01092934 boost::serialization::singleton<boost::archive::detail::pointer_oserializer<boost::archive::binaryTerm_oarchive,MathWorks::lxe::MatlabIrTree> >::get_instance+00635778
[ 16] 0x000000001631a570 bin\win64\pgo\m_lxe.dll+01090928 boost::serialization::singleton<boost::archive::detail::pointer_oserializer<boost::archive::binaryTerm_oarchive,MathWorks::lxe::MatlabIrTree> >::get_instance+00633772
[ 17] 0x000000001623fc91 bin\win64\pgo\m_lxe.dll+00195729
[ 18] 0x000000001623f906 bin\win64\pgo\m_lxe.dll+00194822
[ 19] 0x000000001623f925 bin\win64\pgo\m_lxe.dll+00194853
[ 20] 0x00000000155dca93 bin\win64\pgo\m_dispatcher.dll+00117395 Mfh_file::dispatch_fh_impl+00000835
[ 21] 0x00000000155dc73e bin\win64\pgo\m_dispatcher.dll+00116542 Mfh_file::dispatch_fh+00000062
[ 22] 0x00000000155ca8d8 bin\win64\pgo\m_dispatcher.dll+00043224 Mfunction_handle::dispatch+00001032
[ 23] 0x000000001624794e bin\win64\pgo\m_lxe.dll+00227662
[ 24] 0x0000000016244571 bin\win64\pgo\m_lxe.dll+00214385
[ 25] 0x000000001624b3a6 bin\win64\pgo\m_lxe.dll+00242598
[ 26] 0x000000001624bfb3 bin\win64\pgo\m_lxe.dll+00245683
[ 27] 0x000000001624dff5 bin\win64\pgo\m_lxe.dll+00253941
[ 28] 0x000000001624d44f bin\win64\pgo\m_lxe.dll+00250959
[ 29] 0x000000001624d822 bin\win64\pgo\m_lxe.dll+00251938
[ 30] 0x000000001631331b bin\win64\pgo\m_lxe.dll+01061659 boost::serialization::singleton<boost::archive::detail::pointer_oserializer<boost::archive::binaryTerm_oarchive,MathWorks::lxe::MatlabIrTree> >::get_instance+00604503
[ 31] 0x000000001631ad46 bin\win64\pgo\m_lxe.dll+01092934 boost::serialization::singleton<boost::archive::detail::pointer_oserializer<boost::archive::binaryTerm_oarchive,MathWorks::lxe::MatlabIrTree> >::get_instance+00635778
[ 32] 0x000000001631a570 bin\win64\pgo\m_lxe.dll+01090928 boost::serialization::singleton<boost::archive::detail::pointer_oserializer<boost::archive::binaryTerm_oarchive,MathWorks::lxe::MatlabIrTree> >::get_instance+00633772
[ 33] 0x00000000162aa4d6 bin\win64\pgo\m_lxe.dll+00632022 boost::serialization::singleton<boost::archive::detail::pointer_oserializer<boost::archive::binaryTerm_oarchive,MathWorks::lxe::MatlabIrTree> >::get_instance+00174866
[ 34] 0x00000000162a9ccd bin\win64\pgo\m_lxe.dll+00629965 boost::serialization::singleton<boost::archive::detail::pointer_oserializer<boost::archive::binaryTerm_oarchive,MathWorks::lxe::MatlabIrTree> >::get_instance+00172809
[ 35] 0x00000000162a9be6 bin\win64\pgo\m_lxe.dll+00629734 boost::serialization::singleton<boost::archive::detail::pointer_oserializer<boost::archive::binaryTerm_oarchive,MathWorks::lxe::MatlabIrTree> >::get_instance+00172578
[ 36] 0x00000000162a35a5 bin\win64\pgo\m_lxe.dll+00603557 boost::serialization::singleton<boost::archive::detail::pointer_oserializer<boost::archive::binaryTerm_oarchive,MathWorks::lxe::MatlabIrTree> >::get_instance+00146401
[ 37] 0x00000000162a3532 bin\win64\pgo\m_lxe.dll+00603442 boost::serialization::singleton<boost::archive::detail::pointer_oserializer<boost::archive::binaryTerm_oarchive,MathWorks::lxe::MatlabIrTree> >::get_instance+00146286
[ 38] 0x00000000162a71d5 bin\win64\pgo\m_lxe.dll+00618965 boost::serialization::singleton<boost::archive::detail::pointer_oserializer<boost::archive::binaryTerm_oarchive,MathWorks::lxe::MatlabIrTree> >::get_instance+00161809
[ 39] 0x0000000015725b63 bin\win64\pgo\m_interpreter.dll+00416611 inEvalCmdWithLocalReturn+00000063
[ 40] 0x00000000fb60de26 bin\win64\libmwbridge.dll+00122406 mnParser+00001254
[ 41] 0x00000000153abdb1 bin\win64\mcr.dll+00245169 mcr::runtime::setInterpreterThreadSingletonToCurrent+00029793
[ 42] 0x00000000153aace5 bin\win64\mcr.dll+00240869 mcr::runtime::setInterpreterThreadSingletonToCurrent+00025493
[ 43] 0x00000000153aad53 bin\win64\mcr.dll+00240979 mcr::runtime::setInterpreterThreadSingletonToCurrent+00025603
[ 44] 0x00000000153ab6e1 bin\win64\mcr.dll+00243425 mcr::runtime::setInterpreterThreadSingletonToCurrent+00028049
[ 45] 0x00000000fd02cc77 bin\win64\iqm.dll+00642167 iqm::UserEvalPlugin::pre+00028951
[ 46] 0x00000000fd039cfc bin\win64\iqm.dll+00695548 iqm::UserEvalPlugin::pre+00082332
[ 47] 0x00000000fd02737f bin\win64\iqm.dll+00619391 iqm::UserEvalPlugin::pre+00006175
[ 48] 0x00000000fd02cc16 bin\win64\iqm.dll+00642070 iqm::UserEvalPlugin::pre+00028854
[ 49] 0x00000000fd027863 bin\win64\iqm.dll+00620643 iqm::UserEvalPlugin::pre+00007427
[ 50] 0x00000000fd03c8b6 bin\win64\iqm.dll+00706742 iqm::UserEvalPlugin::pre+00093526
[ 51] 0x00000000fd0080f7 bin\win64\iqm.dll+00491767 iqm::PackagedTaskPlugin::PackagedTaskPlugin+00000759
[ 52] 0x00000000fd0088bf bin\win64\iqm.dll+00493759 iqm::PackagedTaskPlugin::execute+00000879
[ 53] 0x00000000fd00817d bin\win64\iqm.dll+00491901 iqm::PackagedTaskPlugin::PackagedTaskPlugin+00000893
[ 54] 0x00000000fd008708 bin\win64\iqm.dll+00493320 iqm::PackagedTaskPlugin::execute+00000440
[ 55] 0x00000000fcfdbd3a bin\win64\iqm.dll+00310586 iqm::Iqm::setupIqmFcnPtrs+00079802
[ 56] 0x00000000fcfdbc06 bin\win64\iqm.dll+00310278 iqm::Iqm::setupIqmFcnPtrs+00079494
[ 57] 0x00000000fcfbf5be bin\win64\iqm.dll+00193982 iqm::Iqm::deliver+00004046
[ 58] 0x00000000fcfc0545 bin\win64\iqm.dll+00197957 iqm::Iqm::deliver+00008021
[ 59] 0x00000001001237c1 bin\win64\libmwservices.dll+01259457 services::system_events::PpeDispatchHook::dispatchOne+00021505
[ 60] 0x0000000100128663 bin\win64\libmwservices.dll+01279587 sysq::addProcessPendingEventsUnitTestHook+00002211
[ 61] 0x0000000100128850 bin\win64\libmwservices.dll+01280080 sysq::addProcessPendingEventsUnitTestHook+00002704
[ 62] 0x0000000100129c26 bin\win64\libmwservices.dll+01285158 sysq::getCondition+00003462
[ 63] 0x000000010012ac66 bin\win64\libmwservices.dll+01289318 svWS_ProcessPendingEvents+00000230
[ 64] 0x00000000153ac244 bin\win64\mcr.dll+00246340 mcr::runtime::setInterpreterThreadSingletonToCurrent+00030964
[ 65] 0x00000000153ac964 bin\win64\mcr.dll+00248164 mcr::runtime::setInterpreterThreadSingletonToCurrent+00032788
[ 66] 0x00000000153a2762 bin\win64\mcr.dll+00206690 mcr_process_events+00008818
[ 67] 0x00000000152423c5 bin\win64\MVMLocal.dll+00271301 mvm_server::inproc::LocalFactory::terminate+00088005
[ 68] 0x00000000fa957669 bin\win64\mvm.dll+01209961 mvm::detail::initLocalMvmHack+00000569
[ 69] 0x00000000fa957e2b bin\win64\mvm.dll+01211947 mvm::detail::SessionImpl::privateSession+00000555
[ 70] 0x00000000fa958051 bin\win64\mvm.dll+01212497 mvm::detail::SessionImpl::privateSession+00001105
[ 71] 0x0000000140007833 bin\win64\MATLAB.exe+00030771
[ 72] 0x000000014000863f bin\win64\MATLAB.exe+00034367
[ 73] 0x00007ffaa92a3034 C:\WINDOWS\System32\KERNEL32.DLL+00077876 BaseThreadInitThunk+00000020
[ 74] 0x00007ffaa99c1431 C:\WINDOWS\SYSTEM32\ntdll.dll+00463921 RtlUserThreadStart+00000033
我最后应该注意到我正在使用MATLAB 2017b，并且我的编译器是MinGW64 v5.3.0。
答案 0 :(得分：3)
您的代码中存在多个错误，其中大多数会导致段错误并杀死MATLAB。我建议您阅读（或重新阅读）有关mex文件的一些基本文档，例如Create C Source MEX File。
根据文档，mxGetData仅用于获取指向非数字数据的指针，并返回指向void的指针。您的snrf函数需要双精度的指针，因此推测对mex文件的输入应该是标量。在这种情况下，您应该使用mxGetScalar，它返回一个双精度型，因此您可以将这些双精度型的地址传递给函数。您还应该使用mxIsScalar之类的功能来检查用户确实输入了标量。
在尝试使用plhs[0]访问指向数字数据的指针之前，还必须为mxGetPr分配内存。但就您而言，由于（至少我怀疑）您尝试输出标量，因此您可以使用mxCreateDoubleScalar
plhs[0] = mxCreateDoubleScalar(output_from_snrf)
但是，您的函数snrf不会创建/返回输出（也不会更改输入所指向的任何值），因此您需要查看一些基本的C教程以了解如何先这样做。