• Ish (31/31) Dec 02 2015 The following code does core dump (compiled with gdc). Pointers
• Alex Parrill (5/36) Dec 02 2015 You never initialize Mutex, so it is a null pointer when you call

Ish <ratta1i cmich.edu> writes:

The following code does core dump (compiled with gdc). Pointers 
will be appreciated.
import std.stdio;
import std.conv;
import std.math;
import std.concurrency;
import core.thread;
import core.sync.mutex;

enum count = 5;
__gshared double rslt = 0.0;
__gshared Mutex mutex;

void term(immutable(int)* nterm) {
	double r;
	auto n = to!double(*nterm);
	r = 4.0*pow(-1.0, *nterm)/(2.0*n + 1);
	writefln("%s: %6.6f.", *nterm, r);
	mutex.lock();
	   rslt = rslt + r;
	mutex.unlock();
}


void main() {

     foreach (i; 0 .. count) {
	int* jm = new int;
         *jm = i;
	immutable int *j = cast(immutable) jm;
         Tid tid = spawn(&term, j);
     }

     thread_joinAll();
     writefln("Result: %6.9f.", rslt);
}

-ish

Alex Parrill <initrd.gz gmail.com> writes:

On Wednesday, 2 December 2015 at 13:55:02 UTC, Ish wrote:
 The following code does core dump (compiled with gdc). Pointers 
 will be appreciated.
 import std.stdio;
 import std.conv;
 import std.math;
 import std.concurrency;
 import core.thread;
 import core.sync.mutex;

 enum count = 5;
 __gshared double rslt = 0.0;
 __gshared Mutex mutex;

 void term(immutable(int)* nterm) {
 	double r;
 	auto n = to!double(*nterm);
 	r = 4.0*pow(-1.0, *nterm)/(2.0*n + 1);
 	writefln("%s: %6.6f.", *nterm, r);
 	mutex.lock();
 	   rslt = rslt + r;
 	mutex.unlock();
 }


 void main() {

     foreach (i; 0 .. count) {
 	int* jm = new int;
         *jm = i;
 	immutable int *j = cast(immutable) jm;
         Tid tid = spawn(&term, j);
     }

     thread_joinAll();
     writefln("Result: %6.9f.", rslt);
 }

 -ish

You never initialize Mutex, so it is a null pointer when you call 
`mutex.lock`.

Also, no point in passing a pointer here; just pass `i` instead 
of `j`.