Re: compilation warnings in liboctave/CMatrix.cc

[John W. Eaton]

On 13-Jan-2011, CdeMills wrote:

| 
| 
| John W. Eaton wrote:
| > 
| > On 13-Jan-2011, CdeMills wrote:
| > 
| > | Any idea why this message is produced ?
| > 
| > Part of the answer is that the macro used to call Fortran code inserts
| > a call to setjmp for error handling, but I don't know precisely the
| > rules that GCC uses to decide when the problem can occur.  When a
| > variable is in a register?
| > 
| 
| The following patch remove the warning in dbleLU.cc:
| diff -r a1deab9a6e71 liboctave/dbleLU.cc
| --- a/liboctave/dbleLU.cc     Wed Jan 12 03:40:19 2011 -0500
| +++ b/liboctave/dbleLU.cc     Thu Jan 13 23:12:55 2011 +0100
| @@ -77,7 +77,12 @@
|  
|    octave_idx_type info = 0;
|  
| -  F77_XFCN (dgetrf, DGETRF, (a_nr, a_nc, tmp_data, a_nr, pipvt, info));
| +  // F77_XFCN contains a setjmp() -- save and restore mn trough a volative
| +  {
| +    volatile octave_idx_type saved_mn = mn;
| +    F77_XFCN (dgetrf, DGETRF, (a_nr, a_nc, tmp_data, a_nr, pipvt, info));
| +    mn = saved_mn;
| +  }
|  
|    for (octave_idx_type i = 0; i < mn; i++)
|      pipvt[i] -= 1;

What problem does this solve?  I don't see any warnings when compiling
dbleLU.cc.

jwe