core-builtin: add and use built in shim wrapper for strcspn

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>

Author: ColinIanKing

Makefile.config

@@ -2641,6 +2641,7 @@ functions: \
 	BUILTIN_STDC_ROTATE_RIGHT \
 	BUILTIN_STRCHR \
 	BUILTIN_STRCMP \
+	BUILTIN_STRCSPN \
 	BUILTIN_STRDUP \
 	BUILTIN_STRLEN \
 	BUILTIN_STRNCMP \
@@ -3733,6 +3734,9 @@ BUILTIN_STRCHR:
 BUILTIN_STRCMP:
 	$(call check,test-builtin-strcmp,HAVE_BUILTIN_STRCMP,__builtin_strcmp)
 
+BUILTIN_STRCSPN:
+	$(call check,test-builtin-strcspn,HAVE_BUILTIN_STRCSPN,__builtin_strcspn)
+
 BUILTIN_STRDUP:
 	$(call check,test-builtin-strdup,HAVE_BUILTIN_STRDUP,__builtin_strdup)
 

core-builtin.h

@@ -73,6 +73,12 @@
 #define shim_strcmp(s1, s2)		strcmp((s1), (s2))
 #endif
 
+#if defined(HAVE_BUILTIN_STRCSPN)
+#define shim_strcspn(s, reject)		__builtin_strcspn((s), (reject))
+#else
+#define shim_strcspn(s, reject)		strcspn((s), (reject))
+#endif
+
 #if defined(HAVE_BUILTIN_STRLEN)
 #define shim_strlen(str)		__builtin_strlen((str))
 #else

core-rapl.c

@@ -164,7 +164,7 @@ int stress_rapl_domains_get(stress_rapl_domain_t **rapl_domains)
 
 			(void)shim_memset(domain_name, 0, sizeof(domain_name));
 			if (fgets(domain_name, sizeof(domain_name), fp) != NULL) {
-				const size_t idx = strcspn(domain_name, "\n");
+				const size_t idx = shim_strcspn(domain_name, "\n");
 
 				if (LIKELY(idx < sizeof(domain_name)))
 					domain_name[idx] = '\0';

core-thermal-zone.c

@@ -130,7 +130,7 @@ int stress_tz_init(stress_tz_info_t **tz_info_list)
 
 			(void)shim_memset(type, 0, sizeof(type));
 			if (fgets(type, sizeof(type), fp) != NULL) {
-				const size_t idx = strcspn(type, "\n");
+				const size_t idx = shim_strcspn(type, "\n");
 
 				if (idx < sizeof(type))
 					type[idx] = '\0';

test/test-builtin-strcspn.c

@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2026      Colin Ian King
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+#include <string.h>
+
+
+int main(int argc, char **argv)
+{
+	return (int)__builtin_strcspn("test123\n", "\n");
+}
+