diff --git a/ext/standard/formatted_print.c b/ext/standard/formatted_print.c
index f35d196fb971..ffceabd88220 100644
--- a/ext/standard/formatted_print.c
+++ b/ext/standard/formatted_print.c
@@ -18,8 +18,8 @@
 
 #include <locale.h>
 #ifdef ZTS
-#include "ext/standard/php_string.h" /* for localeconv_r() */
-#define LCONV_DECIMAL_POINT (*lconv.decimal_point)
+#include "ext/standard/php_string.h" /* for localeconv_decimal_point() */
+#define LCONV_DECIMAL_POINT localeconv_decimal_point()
 #else
 #define LCONV_DECIMAL_POINT (*lconv->decimal_point)
 #endif
@@ -221,9 +221,7 @@ php_sprintf_appenddouble(zend_string **buffer, size_t *pos,
 	char *s = NULL;
 	size_t s_len = 0;
 	bool is_negative = false;
-#ifdef ZTS
-	struct lconv lconv;
-#else
+#ifndef ZTS
 	struct lconv *lconv;
 #endif
 
@@ -256,9 +254,7 @@ php_sprintf_appenddouble(zend_string **buffer, size_t *pos,
 		case 'E':
 		case 'f':
 		case 'F':
-#ifdef ZTS
-			localeconv_r(&lconv);
-#else
+#ifndef ZTS
 			lconv = localeconv();
 #endif
 			s = php_conv_fp((fmt == 'f')?'F':fmt, number, 0, precision,
@@ -285,9 +281,7 @@ php_sprintf_appenddouble(zend_string **buffer, size_t *pos,
 
 			char decimal_point = '.';
 			if (fmt == 'g' || fmt == 'G') {
-#ifdef ZTS
-				localeconv_r(&lconv);
-#else
+#ifndef ZTS
 				lconv = localeconv();
 #endif
 				decimal_point = LCONV_DECIMAL_POINT;
diff --git a/ext/standard/php_string.h b/ext/standard/php_string.h
index 86c331f8a7c5..412a4a4fa7a6 100644
--- a/ext/standard/php_string.h
+++ b/ext/standard/php_string.h
@@ -32,6 +32,9 @@ PHP_MINIT_FUNCTION(string_intrin);
 	strnatcmp_ex(a, strlen(a), b, strlen(b), true)
 PHPAPI int strnatcmp_ex(char const *a, size_t a_len, char const *b, size_t b_len, bool is_case_insensitive);
 PHPAPI struct lconv *localeconv_r(struct lconv *out);
+#ifdef ZTS
+PHPAPI char localeconv_decimal_point(void);
+#endif
 PHPAPI char *php_strtr(char *str, size_t len, const char *str_from, const char *str_to, size_t trlen);
 PHPAPI zend_string *php_addslashes(zend_string *str);
 PHPAPI void php_stripslashes(zend_string *str);
diff --git a/ext/standard/string.c b/ext/standard/string.c
index c6e89dcca2e5..87e667392104 100644
--- a/ext/standard/string.c
+++ b/ext/standard/string.c
@@ -19,6 +19,9 @@
 #include "php_string.h"
 #include "php_variables.h"
 #include <locale.h>
+#ifdef HAVE_NL_LANGINFO
+# include <langinfo.h>
+#endif
 #ifdef HAVE_LANGINFO_H
 # include <langinfo.h>
 #endif
@@ -88,6 +91,20 @@ static zend_string *php_hex2bin(const unsigned char *old, const size_t oldlen)
 }
 /* }}} */
 
+#ifdef ZTS
+/* read the decimal point through nl_langinfo() (thread-safe), instead of taking the lock. */
+PHPAPI char localeconv_decimal_point(void)
+{
+#if defined(HAVE_NL_LANGINFO) && (defined(__GLIBC__) || defined(__MUSL__))
+	return *nl_langinfo(RADIXCHAR);
+#else
+	struct lconv lc;
+	localeconv_r(&lc);
+	return *lc.decimal_point;
+#endif
+}
+#endif
+
 /* {{{ localeconv_r
  * glibc's localeconv is not reentrant, so lets make it so ... sorta */
 PHPAPI struct lconv *localeconv_r(struct lconv *out)
diff --git a/main/snprintf.c b/main/snprintf.c
index 73c981a1cee7..9e9655fb70ad 100644
--- a/main/snprintf.c
+++ b/main/snprintf.c
@@ -30,7 +30,7 @@
 #include <locale.h>
 #ifdef ZTS
 #include "ext/standard/php_string.h"
-#define LCONV_DECIMAL_POINT (*lconv.decimal_point)
+#define LCONV_DECIMAL_POINT localeconv_decimal_point()
 #else
 #define LCONV_DECIMAL_POINT (*lconv->decimal_point)
 #endif
@@ -491,9 +491,7 @@ static size_t format_converter(buffy * odp, const char *fmt, va_list ap) /* {{{
 	char num_buf[NUM_BUF_SIZE];
 	char char_buf[2];			/* for printing %% and %<unknown> */
 
-#ifdef ZTS
-	struct lconv lconv;
-#else
+#ifndef ZTS
 	struct lconv *lconv = NULL;
 #endif
 
@@ -843,9 +841,7 @@ static size_t format_converter(buffy * odp, const char *fmt, va_list ap) /* {{{
 						s = "INF";
 						s_len = 3;
 					} else {
-#ifdef ZTS
-						localeconv_r(&lconv);
-#else
+#ifndef ZTS
 						if (!lconv) {
 							lconv = localeconv();
 						}
@@ -902,9 +898,7 @@ static size_t format_converter(buffy * odp, const char *fmt, va_list ap) /* {{{
 					/*
 					 * * We use &num_buf[ 1 ], so that we have room for the sign
 					 */
-#ifdef ZTS
-					localeconv_r(&lconv);
-#else
+#ifndef ZTS
 					if (!lconv) {
 						lconv = localeconv();
 					}
diff --git a/main/spprintf.c b/main/spprintf.c
index 6553853d8104..74d2b43cc4f3 100644
--- a/main/spprintf.c
+++ b/main/spprintf.c
@@ -88,7 +88,7 @@
 #include <locale.h>
 #ifdef ZTS
 #include "ext/standard/php_string.h"
-#define LCONV_DECIMAL_POINT (*lconv.decimal_point)
+#define LCONV_DECIMAL_POINT localeconv_decimal_point()
 #else
 #define LCONV_DECIMAL_POINT (*lconv->decimal_point)
 #endif
@@ -196,9 +196,7 @@ static void xbuf_format_converter(void *xbuf, bool is_char, const char *fmt, va_
 	char num_buf[NUM_BUF_SIZE];
 	char char_buf[2];			/* for printing %% and %<unknown> */
 
-#ifdef ZTS
-	struct lconv lconv;
-#else
+#ifndef ZTS
 	struct lconv *lconv = NULL;
 #endif
 
@@ -556,9 +554,7 @@ static void xbuf_format_converter(void *xbuf, bool is_char, const char *fmt, va_
 						s = "inf";
 						s_len = 3;
 					} else {
-#ifdef ZTS
-						localeconv_r(&lconv);
-#else
+#ifndef ZTS
 						if (!lconv) {
 							lconv = localeconv();
 						}
@@ -614,9 +610,7 @@ static void xbuf_format_converter(void *xbuf, bool is_char, const char *fmt, va_
 					/*
 					 * * We use &num_buf[ 1 ], so that we have room for the sign
 					 */
-#ifdef ZTS
-					localeconv_r(&lconv);
-#else
+#ifndef ZTS
 					if (!lconv) {
 						lconv = localeconv();
 					}