Accessing Non-Scalar Arrays with ceval

2012 6 11
1 个回答
回答已采纳
3 次查看（30 天）

0 个投票

Hi,
I'm trying to use the Matlab "mat" and "mx" C-libraries to use .mat-files inside of a Matlab function I'm compiling with the Matlab Coder. I can do this successfully for a scalar variable, but I'm having trouble getting non-scalar arrays in. Because coder.ceval can only return a scalar, my best guess of how to do this at the moment is to use the C "memcpy" function with a coder.wref input.
Here's what I've got right now, referencing a .mat-file "testmat.mat" that has one variable in it, a 1x4 double:
y = ones(1,4);
SS_Table_File = coder.opaque('MATFile *');
rr = ['r',char(0)];
SS_Table_file = coder.ceval('matOpen','testmat.mat',rr);
Xp = coder.opaque('mxArray *');
XX = ['X',char(0)];
Xp = coder.ceval('matGetVariable',SS_Table_file,XX);
coder.ceval('matClose',SS_Table_file);
yp = coder.opaque('double *');
yp = coder.ceval('mxGetPr',Xp);
coder.ceval('memcpy',coder.wref(y),yp,int32(4*8));
This currently compiles OK but then produces a segfault (or some other fatal error that crashes Matlab) when I run it.

请先登录，再回答此问题。

 采纳的回答

Greg
Greg 2012-6-13

0 个投票

Apparently the above code would actually work OK if size_t were a 32-bit integer (which I had assumed it was). On my 64-bit linux machine that defines size_t as an unsigned long int (a uint64), I have to do something like this since the Matlab coder doesn't support 64-bit integers:
sz = coder.opaque('size_t');
sz = coder.ceval('(size_t)',4*8);
coder.ceval('memcpy',coder.wref(y),yp,sz);

更多回答（0 个）

类别

在 帮助中心 和 File Exchange 中查找有关 Deployment, Integration, and Supported Hardware 的更多信息

产品

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by