diff --git a/src/emu/emuopts.c b/src/emu/emuopts.c
index 148facf5cc4..0a71dd3afe5 100644
--- a/src/emu/emuopts.c
+++ b/src/emu/emuopts.c
@@ -582,7 +582,7 @@ const char *emu_options::sub_value(std::string &buffer, const char *name, const
 {
 	std::string tmp = std::string(",").append(subname).append("=");
 	buffer = value(name);
-	int pos = buffer.find(tmp.c_str());
+	int pos = buffer.find(tmp);
 	if (pos != -1)
 	{
 		int endpos = buffer.find_first_of(',', pos + 1);
diff --git a/src/emu/info.c b/src/emu/info.c
index 25ea424130f..8cdf12f1ded 100644
--- a/src/emu/info.c
+++ b/src/emu/info.c
@@ -645,7 +645,7 @@ void info_xml_creator::output_chips(device_t &device, const char *root_tag)
 		if (strcmp(exec->device().tag(), device.tag()))
 		{
 			std::string newtag(exec->device().tag()), oldtag(":");
-			newtag = newtag.substr(newtag.find(oldtag.append(root_tag).c_str()) + oldtag.length());
+			newtag = newtag.substr(newtag.find(oldtag.append(root_tag)) + oldtag.length());
 
 			fprintf(m_output, "\t\t<chip");
 			fprintf(m_output, " type=\"cpu\"");
@@ -663,7 +663,7 @@ void info_xml_creator::output_chips(device_t &device, const char *root_tag)
 		if (strcmp(sound->device().tag(), device.tag()))
 		{
 			std::string newtag(sound->device().tag()), oldtag(":");
-			newtag = newtag.substr(newtag.find(oldtag.append(root_tag).c_str()) + oldtag.length());
+			newtag = newtag.substr(newtag.find(oldtag.append(root_tag)) + oldtag.length());
 
 			fprintf(m_output, "\t\t<chip");
 			fprintf(m_output, " type=\"audio\"");
@@ -691,7 +691,7 @@ void info_xml_creator::output_display(device_t &device, const char *root_tag)
 		if (strcmp(screendev->tag(), device.tag()))
 		{
 			std::string newtag(screendev->tag()), oldtag(":");
-			newtag = newtag.substr(newtag.find(oldtag.append(root_tag).c_str()) + oldtag.length());
+			newtag = newtag.substr(newtag.find(oldtag.append(root_tag)) + oldtag.length());
 
 			fprintf(m_output, "\t\t<display");
 			fprintf(m_output, " tag=\"%s\"", xml_normalize_string(newtag.c_str()));
@@ -1097,7 +1097,7 @@ void info_xml_creator::output_switches(const ioport_list &portlist, const char *
 				std::string output;
 
 				std::string newtag(port->tag()), oldtag(":");
-				newtag = newtag.substr(newtag.find(oldtag.append(root_tag).c_str()) + oldtag.length());
+				newtag = newtag.substr(newtag.find(oldtag.append(root_tag)) + oldtag.length());
 
 				// output the switch name information
 				std::string normalized_field_name(xml_normalize_string(field->name()));
@@ -1228,7 +1228,7 @@ void info_xml_creator::output_images(device_t &device, const char *root_tag)
 		if (strcmp(imagedev->device().tag(), device.tag()))
 		{
 			std::string newtag(imagedev->device().tag()), oldtag(":");
-			newtag = newtag.substr(newtag.find(oldtag.append(root_tag).c_str()) + oldtag.length());
+			newtag = newtag.substr(newtag.find(oldtag.append(root_tag)) + oldtag.length());
 
 			// print m_output device type
 			fprintf(m_output, "\t\t<device type=\"%s\"", xml_normalize_string(imagedev->image_type_name()));
@@ -1286,7 +1286,7 @@ void info_xml_creator::output_slots(device_t &device, const char *root_tag)
 		if (strcmp(slot->device().tag(), device.tag()))
 		{
 			std::string newtag(slot->device().tag()), oldtag(":");
-			newtag = newtag.substr(newtag.find(oldtag.append(root_tag).c_str()) + oldtag.length());
+			newtag = newtag.substr(newtag.find(oldtag.append(root_tag)) + oldtag.length());
 
 			// print m_output device type
 			fprintf(m_output, "\t\t<slot name=\"%s\">\n", xml_normalize_string(newtag.c_str()));
diff --git a/src/emu/machine.c b/src/emu/machine.c
index ae85784ed46..16f038e6eb9 100644
--- a/src/emu/machine.c
+++ b/src/emu/machine.c
@@ -206,7 +206,7 @@ TIMER_CALLBACK_MEMBER(running_machine::autoboot_callback)
 	else if (strlen(options().autoboot_command())!=0) {
 		std::string cmd = std::string(options().autoboot_command());
 		strreplace(cmd, "'", "\\'");
-		std::string val = std::string("emu.keypost('").append(cmd.c_str()).append("')").c_str();
+		std::string val = std::string("emu.keypost('").append(cmd).append("')");
 		manager().lua()->load_string(val.c_str());
 	}
 }
@@ -563,7 +563,7 @@ std::string running_machine::get_statename(const char *option)
 
 	// handle %d in the template (for image devices)
 	std::string statename_dev("%d_");
-	int pos = statename_str.find(statename_dev.c_str());
+	int pos = statename_str.find(statename_dev);
 
 	if (pos != -1)
 	{
diff --git a/src/emu/romload.c b/src/emu/romload.c
index fe3104d7f8a..2e64fe20c58 100644
--- a/src/emu/romload.c
+++ b/src/emu/romload.c
@@ -675,7 +675,7 @@ static int open_rom_file(romload_private *romdata, const char *regiontag, const
 			}
 
 			// prepare locations where we have to load from: list/parentname & list/clonename
-			std::string swlist(tag1.c_str());
+			std::string swlist(tag1);
 			tag2.assign(swlist.append(tag4));
 			if (has_parent)
 			{
@@ -1076,7 +1076,7 @@ int open_disk_image(emu_options &options, const game_driver *gamedrv, const rom_
 			}
 
 			// prepare locations where we have to load from: list/parentname (if any) & list/clonename
-			std::string swlist(tag1.c_str());
+			std::string swlist(tag1);
 			tag2.assign(swlist.append(tag4));
 			if (has_parent)
 			{
diff --git a/src/emu/softlist.c b/src/emu/softlist.c
index c2e8dba671a..c90bb6cccdc 100644
--- a/src/emu/softlist.c
+++ b/src/emu/softlist.c
@@ -158,7 +158,7 @@ bool software_part::is_compatible(const software_list_device &swlistdev) const
 	for (int start = 0, end = filt.find_first_of(',',start); end != -1; start = end + 1, end = filt.find_first_of(',', start))
 	{
 		std::string token(filt, start, end - start + 1);
-		if (comp.find(token.c_str()) != -1)
+		if (comp.find(token) != -1)
 			return true;
 	}
 	return false;
@@ -181,7 +181,7 @@ bool software_part::matches_interface(const char *interface_list) const
 
 	// then add a comma to the end of our interface and return true if we find it in the list string
 	std::string our_interface = std::string(m_interface).append(",");
-	return (interfaces.find(our_interface.c_str()) != -1);
+	return (interfaces.find(our_interface) != -1);
 }
 
 
diff --git a/src/emu/video.c b/src/emu/video.c
index adc2888b2e7..bdeb0d33faf 100644
--- a/src/emu/video.c
+++ b/src/emu/video.c
@@ -1126,7 +1126,7 @@ file_error video_manager::open_next(emu_file &file, const char *extension)
 
 	// handle %d in the template (for image devices)
 	std::string snapdev("%d_");
-	int pos = snapstr.find(snapdev.c_str());
+	int pos = snapstr.find(snapdev);
 
 	if (pos != -1)
 	{
diff --git a/src/mame/machine/315-5881_crypt.c b/src/mame/machine/315-5881_crypt.c
index 7997000400d..ec07d1c8380 100644
--- a/src/mame/machine/315-5881_crypt.c
+++ b/src/mame/machine/315-5881_crypt.c
@@ -47,7 +47,7 @@ void sega_315_5881_crypt_device::device_start()
 	save_item(NAME(line_buffer_pos));
 	save_item(NAME(line_buffer_size));
 
-	std::string skey = parameter("key").c_str();
+	std::string skey = parameter("key");
 	if(!skey.empty())
 		key = strtoll(skey.c_str(), 0, 16);
 	else
diff --git a/src/mame/machine/naomim1.c b/src/mame/machine/naomim1.c
index 86f0119f578..84d2db5ecef 100644
--- a/src/mame/machine/naomim1.c
+++ b/src/mame/machine/naomim1.c
@@ -32,7 +32,7 @@ void naomi_m1_board::device_start()
 {
 	naomi_board::device_start();
 
-	std::string skey = parameter("key").c_str();
+	std::string skey = parameter("key");
 	if(!skey.empty())
 		key = strtoll(skey.c_str(), 0, 16);
 	else