Bug 5698 – va_arg sets wrong length for (u)short[]

Created attachment 929 test case demonstrating the problem va_arg sets wrong length for ushort[] the attached program outputs: vararg_: ubyte[].length = 3 ushort[].length = 140737237065760 short[].length = 139885158469104 uint[].length = 3 vararg: ubyte[].length = 3 ushort[].length = 0 short[].length = 0 uint[].length = 3 I tested with D1, but the bug is possibly also existant in D2.

When I compile the test code on D2 Windows (replacing tango.stdc.stdarg -> core.stdc.stdarg), I just get indication of memory corruption: vararg_: ubyte[].length = 18419671623532547 ushort[].length = 18419809062486019 short[].length = 18419860602093571 uint[].length = 18419912141701123 There's this code in the test case: T[] usa; va_arg(ap, _arguments[0],cast(void*) &usa); Are you sure this is correct? Looks wrong to me, remember that static arrays are passed by value.

I am not 100% sure, no. But I just replaced the array declerations with ubyte uba[] = [ 32,33,34]; uint a[] = [1,2,3]; ushort c[] = [ cast(ushort)51, 52, 53 ]; short sc[] = [ cast(short)51, 52, 53 ]; and it resulted in the same problem. I hope initializing them like this does qualify them as dynamic arrays. (?)

The example code (after changing tango.stdc.stdarg to core.stdc.stdarg) doesnt compile anymore (DMD v2.066.1) I'd guess there are newer/better ways to handle this, so I'd recommend closing it. I get: /usr/include/dmd/druntime/import/core/stdc/stdarg.d(67): Error: cannot implicitly convert expression (cast(void*)(cast(uint)p + (tsize + 4u - 1u & 4294967292u))) of type void* to char* main.d(15): Error: template instance core.stdc.stdarg.va_arg!() error instantiating main.d(57): instantiated from here: varar_!ubyte

I downloaded attachment, changed tango to core in both cases, compiles and runs with 2.066.1, and outputs: vararg_: ubyte[].length = 3 ushort[].length = 3 short[].length = 3 uint[].length = 3 vararg: ubyte[].length = 3 ushort[].length = 3 short[].length = 3 uint[].length = 3 On Macos X (64-bit).