passing by reference... my darkest enemy
actual reason below:
In your case (without reference) the compiler generates a temporary object (int) for the first argument of your MyApplication constructor. You pass this temporary int to QApplication’s constructor (with int reference), which saves the address of this reference. Once your MyApplication constructor is done the temporary int is destroyed but QApplication still has its address.
/***************************************************************************/
/* */
/* otvmod.c */
/* */
/* FreeType's OpenType validation module implementation (body). */
/* */
/* Copyright 2004, 2005, 2006, 2007, 2008 by */
/* David Turner, Robert Wilhelm, and Werner Lemberg. */
/* */
/* This file is part of the FreeType project, and may only be used, */
/* modified, and distributed under the terms of the FreeType project */
/* license, LICENSE.TXT. By continuing to use, modify, or distribute */
/* this file you indicate that you have read the license and */
/* understand and accept it fully. */
/* */
/***************************************************************************/
#include <ft2build.h>
#include FT_TRUETYPE_TABLES_H
#include FT_TRUETYPE_TAGS_H
#include FT_OPENTYPE_VALIDATE_H
#include FT_INTERNAL_OBJECTS_H
#include FT_SERVICE_OPENTYPE_VALIDATE_H
#include "otvmod.h"
#include "otvalid.h"
#include "otvcommn.h"
/*************************************************************************/
/* */
/* The macro FT_COMPONENT is used in trace mode. It is an implicit */
/* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log */
/* messages during execution. */
/* */
#undef FT_COMPONENT
#define FT_COMPONENT trace_otvmodule
static FT_Error
otv_load_table( FT_Face face,
FT_Tag tag,
FT_Byte* volatile* table,
FT_ULong* table_len )
{
FT_Error error;
FT_Memory memory = FT_FACE_MEMORY( face );
error = FT_Load_Sfnt_Table( face, tag, 0, NULL, table_len );
if ( error == OTV_Err_Table_Missing )
return OTV_Err_Ok;
if ( error )
goto Exit;
if ( FT_ALLOC( *table, *table_len ) )
goto Exit;
error = FT_Load_Sfnt_Table( face, tag, 0, *table, table_len );
Exit:
return error;
}
static FT_Error
otv_validate( FT_Face volatile face,
FT_UInt ot_flags,
FT_Bytes *ot_base,
FT_Bytes *ot_gdef,
FT_Bytes *ot_gpos,
FT_Bytes *ot_gsub,
FT_Bytes *ot_jstf )
{
FT_Error error = OTV_Err_Ok;
FT_Byte* volatile base;
FT_Byte* volatile gdef;
FT_Byte* volatile gpos;
FT_Byte* volatile gsub;
FT_Byte* volatile jstf;
FT_Byte* volatile math;
FT_ULong len_base, len_gdef, len_gpos, len_gsub, len_jstf;
FT_ULong len_math;
FT_UInt num_glyphs = (FT_UInt)face->num_glyphs;
FT_ValidatorRec volatile valid;
base = gdef = gpos = gsub = jstf = math = NULL;
len_base = len_gdef = len_gpos = len_gsub = len_jstf = len_math = 0;
/*
* XXX: OpenType tables cannot handle 32-bit glyph index,
* although broken TrueType can have 32-bit glyph index.
*/
if ( face->num_glyphs > 0xFFFFL )
{
FT_TRACE1(( "otv_validate: Invalid glyphs index (0x0000FFFF - 0x%08x) ",
face->num_glyphs ));
FT_TRACE1(( "are not handled by OpenType tables\n" ));
num_glyphs = 0xFFFF;
}
/* load tables */
if ( ot_flags & FT_VALIDATE_BASE )
{
error = otv_load_table( face, TTAG_BASE, &base, &len_base );
if ( error )
goto Exit;
}
if ( ot_flags & FT_VALIDATE_GDEF )
{
error = otv_load_table( face, TTAG_GDEF, &gdef, &len_gdef );
if ( error )
goto Exit;
}
if ( ot_flags & FT_VALIDATE_GPOS )
{
error = otv_load_table( face, TTAG_GPOS, &gpos, &len_gpos );
if ( error )
goto Exit;
}
if ( ot_flags & FT_VALIDATE_GSUB )
{
error = otv_load_table( face, TTAG_GSUB, &gsub, &len_gsub );
if ( error )
goto Exit;
}
if ( ot_flags & FT_VALIDATE_JSTF )
{
error = otv_load_table( face, TTAG_JSTF, &jstf, &len_jstf );
if ( error )
goto Exit;
}
if ( ot_flags & FT_VALIDATE_MATH )
{
error = otv_load_table( face, TTAG_MATH, &math, &len_math );
if ( error )
goto Exit;
}
/* validate tables */
if ( base )
{
ft_validator_init( &valid, base, base + len_base, FT_VALIDATE_DEFAULT );
if ( ft_setjmp( valid.jump_buffer ) == 0 )
otv_BASE_validate( base, &valid );
error = valid.error;
if ( error )
goto Exit;
}
if ( gpos )
{
ft_validator_init( &valid, gpos, gpos + len_gpos, FT_VALIDATE_DEFAULT );
if ( ft_setjmp( valid.jump_buffer ) == 0 )
otv_GPOS_validate( gpos, num_glyphs, &valid );
error = valid.error;
if ( error )
goto Exit;
}
if ( gsub )
{
ft_validator_init( &valid, gsub, gsub + len_gsub, FT_VALIDATE_DEFAULT );
if ( ft_setjmp( valid.jump_buffer ) == 0 )
otv_GSUB_validate( gsub, num_glyphs, &valid );
error = valid.error;
if ( error )
goto Exit;
}
if ( gdef )
{
ft_validator_init( &valid, gdef, gdef + len_gdef, FT_VALIDATE_DEFAULT );
if ( ft_setjmp( valid.jump_buffer ) == 0 )
otv_GDEF_validate( gdef, gsub, gpos, num_glyphs, &valid );
error = valid.error;
if ( error )
goto Exit;
}
if ( jstf )
{
ft_validator_init( &valid, jstf, jstf + len_jstf, FT_VALIDATE_DEFAULT );
if ( ft_setjmp( valid.jump_buffer ) == 0 )
otv_JSTF_validate( jstf, gsub, gpos, num_glyphs, &valid );
error = valid.error;
if ( error )
goto Exit;
}
if ( math )
{
ft_validator_init( &valid, math, math + len_math, FT_VALIDATE_DEFAULT );
if ( ft_setjmp( valid.jump_buffer ) == 0 )
otv_MATH_validate( math, num_glyphs, &valid );
error = valid.error;
if ( error )
goto Exit;
}
*ot_base = (FT_Bytes)base;
*ot_gdef = (FT_Bytes)gdef;
*ot_gpos = (FT_Bytes)gpos;
*ot_gsub = (FT_Bytes)gsub;
*ot_jstf = (FT_Bytes)jstf;
Exit:
if ( error )
{
FT_Memory memory = FT_FACE_MEMORY( face );
FT_FREE( base );
FT_FREE( gdef );
FT_FREE( gpos );
FT_FREE( gsub );
FT_FREE( jstf );
}
{
FT_Memory memory = FT_FACE_MEMORY( face );
FT_FREE( math ); /* Can't return this as API is frozen */
}
return error;
}
static
const FT_Service_OTvalidateRec otvalid_interface =
{
otv_validate
};
static
const FT_ServiceDescRec otvalid_services[] =
{
{ FT_SERVICE_ID_OPENTYPE_VALIDATE, &otvalid_interface },
{ NULL, NULL }
};
static FT_Pointer
otvalid_get_service( FT_Module module,
const char* service_id )
{
FT_UNUSED( module );
return ft_service_list_lookup( otvalid_services, service_id );
}
FT_CALLBACK_TABLE_DEF
const FT_Module_Class otv_module_class =
{
0,
sizeof( FT_ModuleRec ),
"otvalid",
0x10000L,
0x20000L,
0, /* module-specific interface */
(FT_Module_Constructor)0,
(FT_Module_Destructor) 0,
(FT_Module_Requester) otvalid_get_service
};
/* END */