Memory allocation problem!

Torbjorn Granlund tg at
Sun Sep 4 00:08:32 CEST 2011

"laojiang" <7850242 at> writes:

  Hi, I have a problem,such as I definite a one dimension array, and allocate it memory, but it did not works:
   int n0,i;
   mpf_t *f_f0;
   double *f0;
   f_f0= ( mpf_t *)malloc(n0 * sizeof( mpf_t *)); 
   f0= ( double *)malloc(n0 * sizeof( double *)); 
    for (n = 0; n < n0+1; n++) 
     for(i =0;i<n0+1;i++ )
        xval[i] = cos(pih *(2.0 *(i+1)-1.0)/(n0+1));
     for(i =0;i<n00;i++ )
   When I run the code,the result is :
   jwe0019i-u The program was terminated abnormally with signal number SIGSEGV.
             signal identifier = SEGV_MAPERR, address not mapped to object
   Error occurs at __gmpf_set
  And when I change the code like this:
    f_f0= ( mpf_t *)malloc(2*n0 * sizeof( mpf_t *)); 
   It can works. Could you tell me the reason? Thanks in advance!

Is this school assignment?

I would suggest that you run your code under a debugger, or else
read it carefully to spot your programming mistake.


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