Return std::string objects by value rather than pass by reference

- strprintf is unaltered, but strformat now takes one fewer argument
- state_string_export still fills a buffer, but has been made const
- get_default_card_software now takes no arguments but returns a string

src/devices/bus/a7800/a78_slot.cpp

@@ -528,7 +528,7 @@ int a78_cart_slot_device::verify_header(char *header)
  get default card software
  -------------------------------------------------*/
 
-void a78_cart_slot_device::get_default_card_software(std::string &result)
+std::string a78_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -586,10 +586,10 @@ void a78_cart_slot_device::get_default_card_software(std::string &result)
 
 		clear();
 
-		result.assign(slot_string);
+		return std::string(slot_string);
 	}
 	else
-		software_get_default_slot(result, "a78_rom");
+		return software_get_default_slot("a78_rom");
 }
 
 

src/devices/bus/a7800/a78_slot.h

@@ -113,7 +113,7 @@ public:
 	virtual device_image_partialhash_func get_partial_hash() const override { return &a78_partialhash; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ8_MEMBER(read_04xx);

src/devices/bus/a800/a800_slot.cpp

@@ -406,7 +406,7 @@ int a800_cart_slot_device::identify_cart_type(UINT8 *header)
  get default card software
  -------------------------------------------------*/
 
-void a800_cart_slot_device::get_default_card_software(std::string &result)
+std::string a800_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -436,14 +436,14 @@ void a800_cart_slot_device::get_default_card_software(std::string &result)
 
 		clear();
 
-		result.assign(slot_string);
+		return std::string(slot_string);
 	}
 	else
-		software_get_default_slot(result, "a800_8k");
+		return software_get_default_slot("a800_8k");
 }
 
 
-void a5200_cart_slot_device::get_default_card_software(std::string &result)
+std::string a5200_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -469,14 +469,14 @@ void a5200_cart_slot_device::get_default_card_software(std::string &result)
 
 		clear();
 
-		result.assign(slot_string);
+		return std::string(slot_string);
 	}
 	else
-		software_get_default_slot(result, "a5200");
+		return software_get_default_slot("a5200");
 }
 
 
-void xegs_cart_slot_device::get_default_card_software(std::string &result)
+std::string xegs_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -504,10 +504,10 @@ void xegs_cart_slot_device::get_default_card_software(std::string &result)
 
 		clear();
 
-		result.assign(slot_string);
+		return std::string(slot_string);
 	}
 	else
-		software_get_default_slot(result, "xegs");
+		return software_get_default_slot("xegs");
 }
 
 

src/devices/bus/a800/a800_slot.h

@@ -113,7 +113,7 @@ public:
 	virtual const char *file_extensions() const override { return "bin,rom,car"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ8_MEMBER(read_80xx);
@@ -142,7 +142,7 @@ public:
 	virtual const char *file_extensions() const override { return "bin,rom,car,a52"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 };
 
 // ======================> xegs_cart_slot_device
@@ -157,7 +157,7 @@ public:
 	virtual const char *file_extensions() const override { return "bin,rom,car"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 };
 
 // device type definition

src/devices/bus/adam/exp.cpp

@@ -124,9 +124,9 @@ bool adam_expansion_slot_device::call_softlist_load(software_list_device &swlist
 //  get_default_card_software -
 //-------------------------------------------------
 
-void adam_expansion_slot_device::get_default_card_software(std::string &result)
+std::string adam_expansion_slot_device::get_default_card_software()
 {
-	software_get_default_slot(result, "standard");
+	return software_get_default_slot("standard");
 }
 
 

src/devices/bus/adam/exp.h

@@ -87,7 +87,7 @@ protected:
 	virtual const option_guide *create_option_guide() const override { return nullptr; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	devcb_write_line   m_write_irq;
 

src/devices/bus/apf/slot.cpp

@@ -221,7 +221,7 @@ bool apf_cart_slot_device::call_softlist_load(software_list_device &swlist, cons
  get default card software
  -------------------------------------------------*/
 
-void apf_cart_slot_device::get_default_card_software(std::string &result)
+std::string apf_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -240,11 +240,10 @@ void apf_cart_slot_device::get_default_card_software(std::string &result)
 		//printf("type: %s\n", slot_string);
 		clear();
 
-		result.assign(slot_string);
-		return;
+		return std::string(slot_string);
 	}
 
-	software_get_default_slot(result, "std");
+	return software_get_default_slot("std");
 }
 
 /*-------------------------------------------------

src/devices/bus/apf/slot.h

@@ -84,7 +84,7 @@ public:
 	virtual const char *file_extensions() const override { return "bin"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ8_MEMBER(read_rom);

src/devices/bus/arcadia/slot.cpp

@@ -230,9 +230,9 @@ bool arcadia_cart_slot_device::call_softlist_load(software_list_device &swlist,
  get default card software
  -------------------------------------------------*/
 
-void arcadia_cart_slot_device::get_default_card_software(std::string &result)
+std::string arcadia_cart_slot_device::get_default_card_software()
 {
-	software_get_default_slot(result, "std");
+	return software_get_default_slot("std");
 }
 
 /*-------------------------------------------------

src/devices/bus/arcadia/slot.h

@@ -73,7 +73,7 @@ public:
 	virtual const char *file_extensions() const override { return "bin"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ8_MEMBER(read_rom);

src/devices/bus/astrocde/slot.cpp

@@ -198,7 +198,7 @@ bool astrocade_cart_slot_device::call_softlist_load(software_list_device &swlist
  get default card software
  -------------------------------------------------*/
 
-void astrocade_cart_slot_device::get_default_card_software(std::string &result)
+std::string astrocade_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -216,11 +216,10 @@ void astrocade_cart_slot_device::get_default_card_software(std::string &result)
 		//printf("type: %s\n", slot_string);
 		clear();
 
-		result.assign(slot_string);
-		return;
+		return std::string(slot_string);
 	}
 
-	software_get_default_slot(result, "rom");
+	return software_get_default_slot("rom");
 }
 
 /*-------------------------------------------------

src/devices/bus/astrocde/slot.h

@@ -73,7 +73,7 @@ public:
 	virtual const char *file_extensions() const override { return "bin"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ8_MEMBER(read_rom);

src/devices/bus/c64/exp.cpp

@@ -217,20 +217,17 @@ bool c64_expansion_slot_device::call_softlist_load(software_list_device &swlist,
 //  get_default_card_software -
 //-------------------------------------------------
 
-void c64_expansion_slot_device::get_default_card_software(std::string &result)
+std::string c64_expansion_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
 		if (!core_stricmp(filetype(), "crt"))
-		{
-			cbm_crt_get_card(result, m_file);
-			return;
-		}
+			return cbm_crt_get_card(m_file);
 
 		clear();
 	}
 
-	software_get_default_slot(result, "standard");
+	return software_get_default_slot("standard");
 }
 
 

src/devices/bus/c64/exp.h

@@ -149,7 +149,7 @@ protected:
 	virtual const option_guide *create_option_guide() const override { return nullptr; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	devcb_read8        m_read_dma_cd;
 	devcb_write8       m_write_dma_cd;

src/devices/bus/cbm2/exp.cpp

@@ -155,9 +155,9 @@ bool cbm2_expansion_slot_device::call_softlist_load(software_list_device &swlist
 //  get_default_card_software -
 //-------------------------------------------------
 
-void cbm2_expansion_slot_device::get_default_card_software(std::string &result)
+std::string cbm2_expansion_slot_device::get_default_card_software()
 {
-	software_get_default_slot(result, "standard");
+	return software_get_default_slot("standard");
 }
 
 

src/devices/bus/cbm2/exp.h

@@ -96,7 +96,7 @@ protected:
 	virtual const option_guide *create_option_guide() const override { return nullptr; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	device_cbm2_expansion_card_interface *m_card;
 };

src/devices/bus/chanf/slot.cpp

@@ -217,7 +217,7 @@ bool channelf_cart_slot_device::call_softlist_load(software_list_device &swlist,
  get default card software
  -------------------------------------------------*/
 
-void channelf_cart_slot_device::get_default_card_software(std::string &result)
+std::string channelf_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -235,10 +235,9 @@ void channelf_cart_slot_device::get_default_card_software(std::string &result)
 		//printf("type: %s\n", slot_string);
 		clear();
 
-		result.assign(slot_string);
-		return;
+		return std::string(slot_string);
 	}
-	software_get_default_slot(result, "chess");
+	return software_get_default_slot("chess");
 }
 
 /*-------------------------------------------------

src/devices/bus/chanf/slot.h

@@ -87,7 +87,7 @@ public:
 	virtual const char *file_extensions() const override { return "bin,chf"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ8_MEMBER(read_rom);

src/devices/bus/coco/cococart.cpp

@@ -364,9 +364,9 @@ bool cococart_slot_device::call_softlist_load(software_list_device &swlist, cons
 //  get_default_card_software
 //-------------------------------------------------
 
-void cococart_slot_device::get_default_card_software(std::string &result)
+std::string cococart_slot_device::get_default_card_software()
 {
-	software_get_default_slot(result, "pak");
+	return software_get_default_slot("pak");
 }
 
 

src/devices/bus/coco/cococart.h

@@ -102,7 +102,7 @@ public:
 	virtual const option_guide *create_option_guide() const override { return nullptr; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing to $FF40-$FF7F
 	DECLARE_READ8_MEMBER(read);

src/devices/bus/coleco/exp.cpp

@@ -112,18 +112,15 @@ bool colecovision_cartridge_slot_device::call_softlist_load(software_list_device
 //  get_default_card_software -
 //-------------------------------------------------
 
-void colecovision_cartridge_slot_device::get_default_card_software(std::string &result)
+std::string colecovision_cartridge_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
 		UINT32 length = core_fsize(m_file);
 		if (length == 0x100000 || length == 0x200000)
-		{
-			software_get_default_slot(result, "xin1");
-			return;
-		}
+			return software_get_default_slot("xin1");
 	}
-	software_get_default_slot(result, "standard");
+	return software_get_default_slot("standard");
 }
 
 

src/devices/bus/coleco/exp.h

@@ -93,7 +93,7 @@ protected:
 	virtual const option_guide *create_option_guide() const override { return nullptr; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	device_colecovision_cartridge_interface *m_card;
 };

src/devices/bus/crvision/slot.cpp

@@ -229,7 +229,7 @@ bool crvision_cart_slot_device::call_softlist_load(software_list_device &swlist,
  get default card software
  -------------------------------------------------*/
 
-void crvision_cart_slot_device::get_default_card_software(std::string &result)
+std::string crvision_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -267,11 +267,10 @@ void crvision_cart_slot_device::get_default_card_software(std::string &result)
 		//printf("type: %s\n", slot_string);
 		clear();
 
-		result.assign(slot_string);
-		return;
+		return std::string(slot_string);
 	}
 
-	software_get_default_slot(result, "crv_rom4k");
+	return software_get_default_slot("crv_rom4k");
 }
 
 /*-------------------------------------------------

src/devices/bus/crvision/slot.h

@@ -78,7 +78,7 @@ public:
 	virtual const char *file_extensions() const override { return "bin,rom"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ8_MEMBER(read_rom40);

src/devices/bus/gameboy/gb_slot.cpp

@@ -600,7 +600,7 @@ int base_gb_cart_slot_device::get_cart_type(UINT8 *ROM, UINT32 len)
  get default card software
  -------------------------------------------------*/
 
-void base_gb_cart_slot_device::get_default_card_software(std::string &result)
+std::string base_gb_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -623,23 +623,19 @@ void base_gb_cart_slot_device::get_default_card_software(std::string &result)
 		//printf("type: %s\n", slot_string);
 		clear();
 
-		result.assign(slot_string);
-		return;
+		return std::string(slot_string);
 	}
 
-	software_get_default_slot(result, "rom");
+	return software_get_default_slot("rom");
 }
 
 
-void megaduck_cart_slot_device::get_default_card_software(std::string &result)
+std::string megaduck_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
-	{
-		result.assign("rom");
-		return;
-	}
+		return std::string("rom");
 
-	software_get_default_slot(result, "rom");
+	return software_get_default_slot("rom");
 }
 
 

src/devices/bus/gameboy/gb_slot.h

@@ -141,7 +141,7 @@ public:
 	virtual const char *file_extensions() const override { return "bin,gb,gbc"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ8_MEMBER(read_rom);
@@ -182,7 +182,7 @@ public:
 	virtual const char *file_extensions() const override { return "bin"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 };
 
 

src/devices/bus/gba/gba_slot.cpp

@@ -400,7 +400,7 @@ int gba_cart_slot_device::get_cart_type(UINT8 *ROM, UINT32 len)
  get default card software
  -------------------------------------------------*/
 
-void gba_cart_slot_device::get_default_card_software(std::string &result)
+std::string gba_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -417,11 +417,10 @@ void gba_cart_slot_device::get_default_card_software(std::string &result)
 		//printf("type: %s\n", slot_string);
 		clear();
 
-		result.assign(slot_string);
-		return;
+		return std::string(slot_string);
 	}
 
-	software_get_default_slot(result, "gba_rom");
+	return software_get_default_slot("gba_rom");
 }
 
 /*-------------------------------------------------

src/devices/bus/gba/gba_slot.h

@@ -91,7 +91,7 @@ public:
 	virtual const char *file_extensions() const override { return "gba,bin"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ32_MEMBER(read_rom);

src/devices/bus/generic/slot.cpp

@@ -179,9 +179,9 @@ bool generic_slot_device::call_softlist_load(software_list_device &swlist, const
  get default card software
  -------------------------------------------------*/
 
-void generic_slot_device::get_default_card_software(std::string &result)
+std::string generic_slot_device::get_default_card_software()
 {
-	software_get_default_slot(result, m_default_card);
+	return software_get_default_slot(m_default_card);
 }
 
 

src/devices/bus/generic/slot.h

@@ -124,7 +124,7 @@ public:
 	virtual const char *file_extensions() const override { return m_extensions; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ8_MEMBER(read_rom);

src/devices/bus/intv/slot.cpp

@@ -459,7 +459,7 @@ bool intv_cart_slot_device::call_softlist_load(software_list_device &swlist, con
  get default card software
  -------------------------------------------------*/
 
-void intv_cart_slot_device::get_default_card_software(std::string &result)
+std::string intv_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -503,10 +503,9 @@ void intv_cart_slot_device::get_default_card_software(std::string &result)
 		//printf("type: %s\n", slot_string);
 		clear();
 
-		result.assign(slot_string);
-		return;
+		return std::string(slot_string);
 	}
-	software_get_default_slot(result, "intv_rom");
+	return software_get_default_slot("intv_rom");
 }
 
 /*-------------------------------------------------

src/devices/bus/intv/slot.h

@@ -120,7 +120,7 @@ public:
 	virtual const char *file_extensions() const override { return "bin,int,rom,itv"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ16_MEMBER(read_rom04) { if (m_cart) return m_cart->read_rom04(space, offset, mem_mask); else return 0xffff; }

src/devices/bus/iq151/iq151.cpp

@@ -204,7 +204,7 @@ bool iq151cart_slot_device::call_softlist_load(software_list_device &swlist, con
     get default card software
 -------------------------------------------------*/
 
-void iq151cart_slot_device::get_default_card_software(std::string &result)
+std::string iq151cart_slot_device::get_default_card_software()
 {
-	software_get_default_slot(result, "basic6");
+	return software_get_default_slot("basic6");
 }

src/devices/bus/iq151/iq151.h

@@ -106,7 +106,7 @@ public:
 	virtual const option_guide *create_option_guide() const override { return nullptr; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual void read(offs_t offset, UINT8 &data);

src/devices/bus/kc/kc.cpp

@@ -370,7 +370,7 @@ bool kccart_slot_device::call_softlist_load(software_list_device &swlist, const
     get default card software
 -------------------------------------------------*/
 
-void kccart_slot_device::get_default_card_software(std::string &result)
+std::string kccart_slot_device::get_default_card_software()
 {
-	software_get_default_slot(result, "standard");
+	return software_get_default_slot("standard");
 }

src/devices/bus/kc/kc.h

@@ -104,7 +104,7 @@ public:
 	virtual const option_guide *create_option_guide() const override { return nullptr; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 };
 
 // device type definition

src/devices/bus/megadrive/md_slot.cpp

@@ -900,7 +900,7 @@ int base_md_cart_slot_device::get_cart_type(UINT8 *ROM, UINT32 len)
  get default card software
  -------------------------------------------------*/
 
-void base_md_cart_slot_device::get_default_card_software(std::string &result)
+std::string base_md_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -919,10 +919,10 @@ void base_md_cart_slot_device::get_default_card_software(std::string &result)
 
 		clear();
 
-		result.assign(slot_string);
+		return std::string(slot_string);
 	}
 	else
-		software_get_default_slot(result, "rom");
+		return software_get_default_slot("rom");
 }
 
 

src/devices/bus/megadrive/md_slot.h

@@ -161,7 +161,7 @@ public:
 	virtual const option_guide *create_option_guide() const override { return nullptr; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	int get_type() { return m_type; }
 

src/devices/bus/msx_slot/cartridge.cpp

@@ -278,7 +278,7 @@ int msx_slot_cartridge_device::get_cart_type(UINT8 *rom, UINT32 length)
 }
 
 
-void msx_slot_cartridge_device::get_default_card_software(std::string &result)
+std::string msx_slot_cartridge_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -337,10 +337,9 @@ void msx_slot_cartridge_device::get_default_card_software(std::string &result)
 			slot_string = msx_cart_get_slot_option(type);
 		}
 
-		result.assign(slot_string);
-		return;
+		return std::string(slot_string);
 	}
-	software_get_default_slot(result, "nomapper");
+	return software_get_default_slot("nomapper");
 }
 
 

src/devices/bus/msx_slot/cartridge.h

@@ -55,7 +55,7 @@ public:
 	virtual const char *file_extensions() const override { return "mx1,bin,rom"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// msx_internal_slot-level overrides
 	virtual DECLARE_READ8_MEMBER(read) override;

src/devices/bus/neogeo/neogeo_slot.cpp

@@ -204,9 +204,9 @@ bool neogeo_cart_slot_device::call_softlist_load(software_list_device &swlist, c
  get default card software
  -------------------------------------------------*/
 
-void neogeo_cart_slot_device::get_default_card_software(std::string &result)
+std::string neogeo_cart_slot_device::get_default_card_software()
 {
-	software_get_default_slot(result, "rom");
+	return software_get_default_slot("rom");
 }
 
 /*-------------------------------------------------

src/devices/bus/neogeo/neogeo_slot.h

@@ -41,7 +41,7 @@ public:
 	virtual const char *file_extensions() const override { return "bin"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ16_MEMBER(read_rom);

src/devices/bus/nes/aladdin.cpp

@@ -142,7 +142,7 @@ bool nes_aladdin_slot_device::call_softlist_load(software_list_device &swlist, c
 	return TRUE;
 }
 
-void nes_aladdin_slot_device::get_default_card_software(std::string &result)
+std::string nes_aladdin_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -163,10 +163,10 @@ void nes_aladdin_slot_device::get_default_card_software(std::string &result)
 
 		clear();
 
-		result.assign(slot_string);
+		return std::string(slot_string);
 	}
 	else
-		software_get_default_slot(result, "algn");
+		return software_get_default_slot("algn");
 }
 
 

src/devices/bus/nes/aladdin.h

@@ -65,7 +65,7 @@ public:
 	virtual const option_guide *create_option_guide() const override { return nullptr; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	virtual DECLARE_READ8_MEMBER(read);
 	void write_prg(UINT32 offset, UINT8 data) { if (m_cart) m_cart->write_prg(offset, data); }

src/devices/bus/nes/datach.cpp

@@ -143,10 +143,10 @@ bool nes_datach_slot_device::call_softlist_load(software_list_device &swlist, co
 	return TRUE;
 }
 
-void nes_datach_slot_device::get_default_card_software(std::string &result)
+std::string nes_datach_slot_device::get_default_card_software()
 {
 	// any way to detect the game with X24C01?
-	software_get_default_slot(result, "datach_rom");
+	return software_get_default_slot("datach_rom");
 }
 
 

src/devices/bus/nes/datach.h

@@ -67,7 +67,7 @@ public:
 	virtual const option_guide *create_option_guide() const override { return nullptr; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	virtual DECLARE_READ8_MEMBER(read);
 	void write_prg_bank(UINT8 bank) { if (m_cart) m_cart->write_prg_bank(bank); }

src/devices/bus/nes/karastudio.cpp

@@ -132,9 +132,9 @@ bool nes_kstudio_slot_device::call_softlist_load(software_list_device &swlist, c
 	return TRUE;
 }
 
-void nes_kstudio_slot_device::get_default_card_software(std::string &result)
+std::string nes_kstudio_slot_device::get_default_card_software()
 {
-	software_get_default_slot(result, "ks_exp");
+	return software_get_default_slot("ks_exp");
 }
 
 

src/devices/bus/nes/karastudio.h

@@ -64,7 +64,7 @@ public:
 	virtual const option_guide *create_option_guide() const override { return nullptr; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	virtual DECLARE_READ8_MEMBER(read);
 	void write_prg_bank(UINT8 bank) { if (m_cart) m_cart->write_prg_bank(bank); }

src/devices/bus/nes/nes_slot.cpp

@@ -912,7 +912,7 @@ bool nes_cart_slot_device::call_softlist_load(software_list_device &swlist, cons
  get default card software
  -------------------------------------------------*/
 
-void nes_cart_slot_device::get_default_card_software(std::string &result)
+std::string nes_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -930,10 +930,10 @@ void nes_cart_slot_device::get_default_card_software(std::string &result)
 
 		clear();
 
-		result.assign(slot_string);
+		return std::string(slot_string);
 	}
 	else
-		software_get_default_slot(result, "nrom");
+		return software_get_default_slot("nrom");
 }
 
 

src/devices/bus/nes/nes_slot.h

@@ -363,7 +363,7 @@ public:
 	virtual device_image_partialhash_func get_partial_hash() const override { return &nes_partialhash; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 	const char * get_default_card_ines(UINT8 *ROM, UINT32 len);
 	const char * get_default_card_unif(UINT8 *ROM, UINT32 len);
 	const char * nes_get_slot(int pcb_id);

src/devices/bus/nes/sunsoft_dcs.cpp

@@ -111,9 +111,9 @@ bool nes_ntb_slot_device::call_softlist_load(software_list_device &swlist, const
 	return TRUE;
 }
 
-void nes_ntb_slot_device::get_default_card_software(std::string &result)
+std::string nes_ntb_slot_device::get_default_card_software()
 {
-	software_get_default_slot(result, "ntbrom");
+	return software_get_default_slot("ntbrom");
 }
 
 //-----------------------------------------------

src/devices/bus/nes/sunsoft_dcs.h

@@ -61,7 +61,7 @@ public:
 	virtual const option_guide *create_option_guide() const override { return nullptr; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	virtual DECLARE_READ8_MEMBER(read);
 

src/devices/bus/odyssey2/slot.cpp

@@ -209,7 +209,7 @@ bool o2_cart_slot_device::call_softlist_load(software_list_device &swlist, const
  get default card software
  -------------------------------------------------*/
 
-void o2_cart_slot_device::get_default_card_software(std::string &result)
+std::string o2_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -227,11 +227,10 @@ void o2_cart_slot_device::get_default_card_software(std::string &result)
 		//printf("type: %s\n", slot_string);
 		clear();
 
-		result.assign(slot_string);
-		return;
+		return std::string(slot_string);
 	}
 
-	software_get_default_slot(result, "o2_rom");
+	return software_get_default_slot("o2_rom");
 }
 
 /*-------------------------------------------------

src/devices/bus/odyssey2/slot.h

@@ -84,7 +84,7 @@ public:
 	virtual const char *file_extensions() const override { return "bin,rom"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ8_MEMBER(read_rom04);

src/devices/bus/pce/pce_slot.cpp

@@ -339,7 +339,7 @@ int pce_cart_slot_device::get_cart_type(UINT8 *ROM, UINT32 len)
  get default card software
  -------------------------------------------------*/
 
-void pce_cart_slot_device::get_default_card_software(std::string &result)
+std::string pce_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -356,11 +356,10 @@ void pce_cart_slot_device::get_default_card_software(std::string &result)
 		//printf("type: %s\n", slot_string);
 		clear();
 
-		result.assign(slot_string);
-		return;
+		return std::string(slot_string);
 	}
 
-	software_get_default_slot(result, "rom");
+	return software_get_default_slot("rom");
 }
 
 /*-------------------------------------------------

src/devices/bus/pce/pce_slot.h

@@ -88,7 +88,7 @@ public:
 	virtual const char *file_extensions() const override { return "pce,bin"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ8_MEMBER(read_cart);

src/devices/bus/plus4/exp.cpp

@@ -157,9 +157,9 @@ bool plus4_expansion_slot_device::call_softlist_load(software_list_device &swlis
 //  get_default_card_software -
 //-------------------------------------------------
 
-void plus4_expansion_slot_device::get_default_card_software(std::string &result)
+std::string plus4_expansion_slot_device::get_default_card_software()
 {
-	software_get_default_slot(result, "standard");
+	return software_get_default_slot("standard");
 }
 
 

src/devices/bus/plus4/exp.h

@@ -135,7 +135,7 @@ protected:
 	virtual const option_guide *create_option_guide() const override { return nullptr; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	devcb_write_line   m_write_irq;
 	devcb_read8        m_read_dma_cd;

src/devices/bus/ql/rom.cpp

@@ -114,9 +114,9 @@ bool ql_rom_cartridge_slot_t::call_softlist_load(software_list_device &swlist, c
 //  get_default_card_software -
 //-------------------------------------------------
 
-void ql_rom_cartridge_slot_t::get_default_card_software(std::string &result)
+std::string ql_rom_cartridge_slot_t::get_default_card_software()
 {
-	software_get_default_slot(result, "standard");
+	return software_get_default_slot("standard");
 }
 
 

src/devices/bus/ql/rom.h

@@ -110,7 +110,7 @@ protected:
 	virtual const option_guide *create_option_guide() const override { return nullptr; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	device_ql_rom_cartridge_card_interface *m_card;
 };

src/devices/bus/saturn/sat_slot.cpp

@@ -219,9 +219,9 @@ bool sat_cart_slot_device::call_softlist_load(software_list_device &swlist, cons
  get default card software
  -------------------------------------------------*/
 
-void sat_cart_slot_device::get_default_card_software(std::string &result)
+std::string sat_cart_slot_device::get_default_card_software()
 {
-	software_get_default_slot(result, "rom");
+	return software_get_default_slot("rom");
 }
 
 

src/devices/bus/saturn/sat_slot.h

@@ -89,7 +89,7 @@ public:
 	virtual const char *file_extensions() const override { return "bin"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ32_MEMBER(read_rom);

src/devices/bus/scv/slot.cpp

@@ -259,7 +259,7 @@ int scv_cart_slot_device::get_cart_type(UINT8 *ROM, UINT32 len)
  get default card software
  -------------------------------------------------*/
 
-void scv_cart_slot_device::get_default_card_software(std::string &result)
+std::string scv_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -276,11 +276,10 @@ void scv_cart_slot_device::get_default_card_software(std::string &result)
 		//printf("type: %s\n", slot_string);
 		clear();
 
-		result.assign(slot_string);
-		return;
+		return std::string(slot_string);
 	}
 
-	software_get_default_slot(result, "rom8k");
+	return software_get_default_slot("rom8k");
 }
 
 /*-------------------------------------------------

src/devices/bus/scv/slot.h

@@ -88,7 +88,7 @@ public:
 	virtual const char *file_extensions() const override { return "bin"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ8_MEMBER(read_cart);

src/devices/bus/sega8/sega8_slot.cpp

@@ -603,7 +603,7 @@ int sega8_cart_slot_device::get_cart_type(UINT8 *ROM, UINT32 len)
  get default card software
  -------------------------------------------------*/
 
-void sega8_cart_slot_device::get_default_card_software(std::string &result)
+std::string sega8_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -623,11 +623,10 @@ void sega8_cart_slot_device::get_default_card_software(std::string &result)
 		//printf("type: %s\n", slot_string);
 		clear();
 
-		result.assign(slot_string);
-		return;
+		return std::string(slot_string);
 	}
 
-	software_get_default_slot(result, "rom");
+	return software_get_default_slot("rom");
 }
 
 

src/devices/bus/sega8/sega8_slot.h

@@ -137,7 +137,7 @@ public:
 	virtual const char *file_extensions() const override { return m_extensions; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ8_MEMBER(read_cart);

src/devices/bus/snes/snes_slot.cpp

@@ -999,7 +999,7 @@ void base_sns_cart_slot_device::get_cart_type_addon(UINT8 *ROM, UINT32 len, int
  get default card software
  -------------------------------------------------*/
 
-void base_sns_cart_slot_device::get_default_card_software(std::string &result)
+std::string base_sns_cart_slot_device::get_default_card_software()
 {
 	bool fullpath = open_image_file(mconfig().options());
 
@@ -1058,11 +1058,10 @@ void base_sns_cart_slot_device::get_default_card_software(std::string &result)
 
 		clear();
 
-		result.assign(slot_string);
-		return;
+		return std::string(slot_string);
 	}
 
-	software_get_default_slot(result, "lorom");
+	return software_get_default_slot("lorom");
 }
 
 

src/devices/bus/snes/snes_slot.h

@@ -180,7 +180,7 @@ public:
 	virtual const option_guide *create_option_guide() const override { return nullptr; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ8_MEMBER(read_l);

src/devices/bus/vboy/slot.cpp

@@ -233,9 +233,9 @@ bool vboy_cart_slot_device::call_softlist_load(software_list_device &swlist, con
  get default card software
  -------------------------------------------------*/
 
-void vboy_cart_slot_device::get_default_card_software(std::string &result)
+std::string vboy_cart_slot_device::get_default_card_software()
 {
-	software_get_default_slot(result, "vb_rom");
+	return software_get_default_slot("vb_rom");
 }
 
 /*-------------------------------------------------

src/devices/bus/vboy/slot.h

@@ -83,7 +83,7 @@ public:
 	virtual const char *file_extensions() const override { return "vb,bin"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ32_MEMBER(read_cart);

src/devices/bus/vc4000/slot.cpp

@@ -235,7 +235,7 @@ bool vc4000_cart_slot_device::call_softlist_load(software_list_device &swlist, c
  get default card software
  -------------------------------------------------*/
 
-void vc4000_cart_slot_device::get_default_card_software(std::string &result)
+std::string vc4000_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -254,11 +254,10 @@ void vc4000_cart_slot_device::get_default_card_software(std::string &result)
 		//printf("type: %s\n", slot_string);
 		clear();
 
-		result.assign(slot_string);
-		return;
+		return std::string(slot_string);
 	}
 
-	software_get_default_slot(result, "std");
+	return software_get_default_slot("std");
 }
 
 /*-------------------------------------------------

src/devices/bus/vc4000/slot.h

@@ -85,7 +85,7 @@ public:
 	virtual const char *file_extensions() const override { return "bin,rom"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ8_MEMBER(read_rom);

src/devices/bus/vcs/vcs_slot.cpp

@@ -781,7 +781,7 @@ int vcs_cart_slot_device::identify_cart_type(UINT8 *ROM, UINT32 len)
  get default card software
  -------------------------------------------------*/
 
-void vcs_cart_slot_device::get_default_card_software(std::string &result)
+std::string vcs_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -797,10 +797,10 @@ void vcs_cart_slot_device::get_default_card_software(std::string &result)
 
 		clear();
 
-		result.assign(slot_string);
+		return std::string(slot_string);
 	}
 	else
-		software_get_default_slot(result, "a26_4k");
+		return software_get_default_slot("a26_4k");
 }
 
 

src/devices/bus/vcs/vcs_slot.h

@@ -112,7 +112,7 @@ public:
 	virtual const char *file_extensions() const override { return "bin,a26"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ8_MEMBER(read_rom);

src/devices/bus/vectrex/slot.cpp

@@ -217,7 +217,7 @@ bool vectrex_cart_slot_device::call_softlist_load(software_list_device &swlist,
  get default card software
  -------------------------------------------------*/
 
-void vectrex_cart_slot_device::get_default_card_software(std::string &result)
+std::string vectrex_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -238,11 +238,10 @@ void vectrex_cart_slot_device::get_default_card_software(std::string &result)
 		//printf("type: %s\n", slot_string);
 		clear();
 
-		result.assign(slot_string);
-		return;
+		return std::string(slot_string);
 	}
 
-	software_get_default_slot(result, "vec_rom");
+	return software_get_default_slot("vec_rom");
 }
 
 /*-------------------------------------------------

src/devices/bus/vectrex/slot.h

@@ -84,7 +84,7 @@ public:
 	virtual const char *file_extensions() const override { return "bin,gam,vec"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ8_MEMBER(read_rom);

src/devices/bus/vic10/exp.cpp

@@ -182,20 +182,17 @@ bool vic10_expansion_slot_device::call_softlist_load(software_list_device &swlis
 //  get_default_card_software -
 //-------------------------------------------------
 
-void vic10_expansion_slot_device::get_default_card_software(std::string &result)
+std::string vic10_expansion_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
 		if (!core_stricmp(filetype(), "crt"))
-		{
-			cbm_crt_get_card(result, m_file);
-			return;
-		}
+			return cbm_crt_get_card(m_file);
 
 		clear();
 	}
 
-	software_get_default_slot(result, "standard");
+	return software_get_default_slot("standard");
 }
 
 

src/devices/bus/vic10/exp.h

@@ -134,7 +134,7 @@ protected:
 	virtual const option_guide *create_option_guide() const override { return nullptr; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	devcb_write_line   m_write_irq;
 	devcb_write_line   m_write_res;

src/devices/bus/vic20/exp.cpp

@@ -167,9 +167,9 @@ bool vic20_expansion_slot_device::call_softlist_load(software_list_device &swlis
 //  get_default_card_software -
 //-------------------------------------------------
 
-void vic20_expansion_slot_device::get_default_card_software(std::string &result)
+std::string vic20_expansion_slot_device::get_default_card_software()
 {
-	software_get_default_slot(result, "standard");
+	return software_get_default_slot("standard");
 }
 
 

src/devices/bus/vic20/exp.h

@@ -125,7 +125,7 @@ protected:
 	virtual const option_guide *create_option_guide() const override { return nullptr; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	devcb_write_line   m_write_irq;
 	devcb_write_line   m_write_nmi;

src/devices/bus/vidbrain/exp.cpp

@@ -154,9 +154,9 @@ bool videobrain_expansion_slot_device::call_softlist_load(software_list_device &
 //  get_default_card_software -
 //-------------------------------------------------
 
-void videobrain_expansion_slot_device::get_default_card_software(std::string &result)
+std::string videobrain_expansion_slot_device::get_default_card_software()
 {
-	software_get_default_slot(result, "standard");
+	return software_get_default_slot("standard");
 }
 
 

src/devices/bus/vidbrain/exp.h

@@ -150,7 +150,7 @@ protected:
 	virtual const option_guide *create_option_guide() const override { return nullptr; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	devcb_write_line   m_write_extres;
 

src/devices/bus/wswan/slot.cpp

@@ -306,7 +306,7 @@ int ws_cart_slot_device::get_cart_type(UINT8 *ROM, UINT32 len, UINT32 &nvram_len
  get default card software
  -------------------------------------------------*/
 
-void ws_cart_slot_device::get_default_card_software(std::string &result)
+std::string ws_cart_slot_device::get_default_card_software()
 {
 	if (open_image_file(mconfig().options()))
 	{
@@ -325,11 +325,10 @@ void ws_cart_slot_device::get_default_card_software(std::string &result)
 		//printf("type: %s\n", slot_string);
 		clear();
 
-		result.assign(slot_string);
-		return;
+		return std::string(slot_string);
 	}
 
-	software_get_default_slot(result, "ws_rom");
+	return software_get_default_slot("ws_rom");
 }
 
 /*-------------------------------------------------

src/devices/bus/wswan/slot.h

@@ -96,7 +96,7 @@ public:
 	virtual const char *file_extensions() const override { return "ws,wsc,bin"; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ8_MEMBER(read_rom20);

src/devices/bus/z88/z88.cpp

@@ -182,9 +182,9 @@ bool z88cart_slot_device::call_softlist_load(software_list_device &swlist, const
     get default card software
 -------------------------------------------------*/
 
-void z88cart_slot_device::get_default_card_software(std::string &result)
+std::string z88cart_slot_device::get_default_card_software()
 {
-	software_get_default_slot(result, "128krom");
+	return software_get_default_slot("128krom");
 }
 
 

src/devices/bus/z88/z88.h

@@ -109,7 +109,7 @@ public:
 	virtual const option_guide *create_option_guide() const override { return nullptr; }
 
 	// slot interface overrides
-	virtual void get_default_card_software(std::string &result) override;
+	virtual std::string get_default_card_software() override;
 
 	// reading and writing
 	virtual DECLARE_READ8_MEMBER(read);

src/devices/cpu/8x300/8x300.cpp

@@ -145,7 +145,7 @@ void n8x300_cpu_device::device_start()
 	m_icountptr = &m_icount;
 }
 
-void n8x300_cpu_device::state_string_export(const device_state_entry &entry, std::string &str)
+void n8x300_cpu_device::state_string_export(const device_state_entry &entry, std::string &str) const
 {
 	switch (entry.index())
 	{

src/devices/cpu/8x300/8x300.h

@@ -66,7 +66,7 @@ protected:
 	}
 
 	// device_state_interface overrides
-	void state_string_export(const device_state_entry &entry, std::string &str) override;
+	virtual void state_string_export(const device_state_entry &entry, std::string &str) const override;
 
 	// device_disasm_interface overrides
 	virtual UINT32 disasm_min_opcode_bytes() const override { return 2; }

src/devices/cpu/adsp2100/adsp2100.cpp

@@ -544,15 +544,14 @@ void adsp21xx_device::device_start()
 	state_add(ADSP2100_SR0_SEC, "SR0_SEC",   m_alt.sr.srx.sr0.u);
 	state_add(ADSP2100_SR1_SEC, "SR1_SEC",   m_alt.sr.srx.sr1.u);
 
-	std::string tempstring;
 	for (int ireg = 0; ireg < 8; ireg++)
-		state_add(ADSP2100_I0 + ireg, strformat(tempstring, "I%d", ireg).c_str(), m_i[ireg]).mask(0x3fff).callimport();
+		state_add(ADSP2100_I0 + ireg, strformat("I%d", ireg).c_str(), m_i[ireg]).mask(0x3fff).callimport();
 
 	for (int lreg = 0; lreg < 8; lreg++)
-		state_add(ADSP2100_L0 + lreg, strformat(tempstring, "L%d", lreg).c_str(), m_l[lreg]).mask(0x3fff).callimport();
+		state_add(ADSP2100_L0 + lreg, strformat("L%d", lreg).c_str(), m_l[lreg]).mask(0x3fff).callimport();
 
 	for (int mreg = 0; mreg < 8; mreg++)
-		state_add(ADSP2100_M0 + mreg, strformat(tempstring, "M%d", mreg).c_str(), m_m[mreg]).signed_mask(0x3fff);
+		state_add(ADSP2100_M0 + mreg, strformat("M%d", mreg).c_str(), m_m[mreg]).signed_mask(0x3fff);
 
 	state_add(ADSP2100_PX,      "PX",        m_px);
 	state_add(ADSP2100_CNTR,    "CNTR",      m_cntr).mask(0x3fff);
@@ -571,7 +570,7 @@ void adsp21xx_device::device_start()
 
 	for (int irqnum = 0; irqnum < 4; irqnum++)
 		if (irqnum < 4 || m_chip_type == CHIP_TYPE_ADSP2100)
-			state_add(ADSP2100_IRQSTATE0 + irqnum, strformat(tempstring, "IRQ%d", irqnum).c_str(), m_irq_state[irqnum]).mask(1).callimport();
+			state_add(ADSP2100_IRQSTATE0 + irqnum, strformat("IRQ%d", irqnum).c_str(), m_irq_state[irqnum]).mask(1).callimport();
 
 	state_add(ADSP2100_FLAGIN,  "FLAGIN",    m_flagin).mask(1);
 	state_add(ADSP2100_FLAGOUT, "FLAGOUT",   m_flagout).mask(1);
@@ -720,7 +719,7 @@ void adsp21xx_device::state_import(const device_state_entry &entry)
 //  for the debugger
 //-------------------------------------------------
 
-void adsp21xx_device::state_string_export(const device_state_entry &entry, std::string &str)
+void adsp21xx_device::state_string_export(const device_state_entry &entry, std::string &str) const
 {
 	switch (entry.index())
 	{

src/devices/cpu/adsp2100/adsp2100.h

@@ -237,7 +237,7 @@ protected:
 
 	// device_state_interface overrides
 	virtual void state_import(const device_state_entry &entry) override;
-	virtual void state_string_export(const device_state_entry &entry, std::string &str) override;
+	virtual void state_string_export(const device_state_entry &entry, std::string &str) const override;
 
 	// device_disasm_interface overrides
 	virtual UINT32 disasm_min_opcode_bytes() const override;

src/devices/cpu/alph8201/alph8201.cpp

@@ -527,7 +527,7 @@ void alpha8201_cpu_device::state_export(const device_state_entry &entry)
 }
 
 
-void alpha8201_cpu_device::state_string_export(const device_state_entry &entry, std::string &str)
+void alpha8201_cpu_device::state_string_export(const device_state_entry &entry, std::string &str) const
 {
 	switch (entry.index())
 	{

src/devices/cpu/alph8201/alph8201.h

@@ -75,7 +75,7 @@ protected:
 	// device_state_interface overrides
 	virtual void state_import(const device_state_entry &entry) override;
 	virtual void state_export(const device_state_entry &entry) override;
-	void state_string_export(const device_state_entry &entry, std::string &str) override;
+	virtual void state_string_export(const device_state_entry &entry, std::string &str) const override;
 
 	// device_disasm_interface overrides
 	virtual UINT32 disasm_min_opcode_bytes() const override { return 1; }

src/devices/cpu/alto2/alto2cpu.cpp

@@ -1002,7 +1002,7 @@ void alto2_cpu_device::device_start()
 //  for the debugger
 //-------------------------------------------------
 
-void alto2_cpu_device::state_string_export(const device_state_entry &entry, std::string &str)
+void alto2_cpu_device::state_string_export(const device_state_entry &entry, std::string &str) const
 {
 	switch (entry.index())
 	{

src/devices/cpu/alto2/alto2cpu.h

@@ -213,7 +213,7 @@ protected:
 	//! device (P)ROMs
 	virtual const rom_entry *device_rom_region() const override;
 	//! device_state_interface overrides
-	void state_string_export(const device_state_entry &entry, std::string &str) override;
+	void state_string_export(const device_state_entry &entry, std::string &str) const override;
 
 	//! device_disasm_interface overrides
 	virtual UINT32 disasm_min_opcode_bytes() const override { return 4; }

src/devices/cpu/am29000/am29000.cpp

@@ -404,7 +404,7 @@ void am29000_cpu_device::device_start()
 }
 
 
-void am29000_cpu_device::state_string_export(const device_state_entry &entry, std::string &str)
+void am29000_cpu_device::state_string_export(const device_state_entry &entry, std::string &str) const
 {
 	switch (entry.index())
 	{

src/devices/cpu/am29000/am29000.h

@@ -462,7 +462,7 @@ protected:
 	}
 
 	// device_state_interface overrides
-	void state_string_export(const device_state_entry &entry, std::string &str) override;
+	void state_string_export(const device_state_entry &entry, std::string &str) const override;
 
 	// device_disasm_interface overrides
 	virtual UINT32 disasm_min_opcode_bytes() const override { return 4; }

src/devices/cpu/amis2000/amis2000.cpp

@@ -70,7 +70,7 @@ amis2152_cpu_device::amis2152_cpu_device(const machine_config &mconfig, const ch
 
 
 // disasm
-void amis2000_base_device::state_string_export(const device_state_entry &entry, std::string &str)
+void amis2000_base_device::state_string_export(const device_state_entry &entry, std::string &str) const
 {
 	switch (entry.index())
 	{

src/devices/cpu/amis2000/amis2000.h

@@ -89,7 +89,7 @@ protected:
 	virtual UINT32 disasm_min_opcode_bytes() const override { return 1; }
 	virtual UINT32 disasm_max_opcode_bytes() const override { return 1; }
 	virtual offs_t disasm_disassemble(char *buffer, offs_t pc, const UINT8 *oprom, const UINT8 *opram, UINT32 options) override;
-	void state_string_export(const device_state_entry &entry, std::string &str) override;
+	virtual void state_string_export(const device_state_entry &entry, std::string &str) const override;
 
 	address_space_config m_program_config;
 	address_space_config m_data_config;

src/devices/cpu/apexc/apexc.cpp

@@ -814,7 +814,7 @@ void apexc_cpu_device::state_export(const device_state_entry &entry)
 }
 
 
-void apexc_cpu_device::state_string_export(const device_state_entry &entry, std::string &str)
+void apexc_cpu_device::state_string_export(const device_state_entry &entry, std::string &str) const
 {
 	switch (entry.index())
 	{

src/devices/cpu/apexc/apexc.h

@@ -44,7 +44,7 @@ protected:
 	// device_state_interface overrides
 	virtual void state_import(const device_state_entry &entry) override;
 	virtual void state_export(const device_state_entry &entry) override;
-	void state_string_export(const device_state_entry &entry, std::string &str) override;
+	virtual void state_string_export(const device_state_entry &entry, std::string &str) const override;
 
 	// device_disasm_interface overrides
 	virtual UINT32 disasm_min_opcode_bytes() const override { return 4; }