https://dev.to/pauljlucas/auto-in-c23-ij9
Reported UpStream : https://github.com/php/pecl-search_engine-solr/issues/96

--- src/php_solr_client.c	2026-05-02 12:04:42
+++ src/php_solr_client.c	2026-05-02 12:28:58
@@ -703,7 +703,7 @@
 
 	if (commitWithin > 0L)
 	{
-		auto char commitWithinBuffer[32];
+		char commitWithinBuffer[32];
 
 		memset(commitWithinBuffer, 0, sizeof(commitWithinBuffer));
 
@@ -854,7 +854,7 @@
 
 	if (commitWithin > 0L)
 	{
-		auto char commitWithinBuffer[32];
+		char commitWithinBuffer[32];
 
 		memset(commitWithinBuffer, 0, sizeof(commitWithinBuffer));
 
--- src/solr_functions_document.c	2026-05-02 12:04:42
+++ src/solr_functions_document.c	2026-05-02 12:28:26
@@ -426,7 +426,7 @@
 
    if (doc_entry->document_boost > 0.0f)
    {
-       auto char tmp_buffer[256]; /* Scratch pad for converting numeric values to strings */
+       char tmp_buffer[256]; /* Scratch pad for converting numeric values to strings */
        memset(tmp_buffer, 0, sizeof(tmp_buffer));
        php_gcvt(doc_entry->document_boost, EG(precision), '.', 'e' , tmp_buffer);
        xmlNewProp(solr_doc_node, (xmlChar *) "boost", (xmlChar *) tmp_buffer);
@@ -507,7 +507,7 @@
             /* Set the boost attribute if this is the first value */
             if (is_first_value && field->field_boost > 0.0f)
             {
-                auto char tmp_boost_value_buffer[256];
+                char tmp_boost_value_buffer[256];
 
                 memset(tmp_boost_value_buffer, 0, sizeof(tmp_boost_value_buffer));
 
--- src/solr_functions_params.c	2026-05-02 12:04:39
+++ src/solr_functions_params.c	2026-05-02 12:28:11
@@ -645,7 +645,7 @@
 	solr_param_value_t *current_ptr = solr_param->head;
 	solr_char_t list_delimiter = ','; /* Comma 0x2C */
 	zend_ulong n_loops = solr_param->count - 1;
-	auto solr_string_t tmp_buffer;
+	solr_string_t tmp_buffer;
 	zend_string *url_encoded_list = NULL;
 
 	solr_string_appends(buffer, solr_param->param_name, solr_param->param_name_length);
@@ -935,7 +935,7 @@
 	solr_param_value_t *current_ptr = solr_param->head;
 	solr_char_t list_delimiter = solr_param->delimiter; /* Comma 0x2C */
 	zend_ulong n_loops = solr_param->count - 1;
-	auto solr_string_t tmp_buffer;
+	solr_string_t tmp_buffer;
 	zend_string *url_encoded_list = NULL;
 
 	solr_string_appends(buffer, solr_param->param_name, solr_param->param_name_length);
--- src/solr_string.c	2026-05-02 12:04:40
+++ src/solr_string.c	2026-05-02 12:24:49
@@ -52,7 +52,7 @@
 /* {{{ PHP_SOLR_API void solr_string_appends(solr_string_t *dest, const solr_char_t *src, size_t length SOLR_MEM_DEBUG_DC) */
 PHP_SOLR_API void solr_string_appends_ex(solr_string_t *dest, const solr_char_t *src, size_t length SOLR_MEM_DEBUG_DC)
 {
-	auto size_t __new_length = 0U;
+	size_t __new_length = 0U;
 
 	/* (Re)allocates memory and increases the capacity if necessary */
 	solr_string_alloc(dest, length, &__new_length SOLR_MEM_DEBUG_CC);
@@ -71,7 +71,7 @@
 /* {{{ PHP_SOLR_API void solr_string_appendc(solr_string_t *dest, solr_char_t ch SOLR_MEM_DEBUG_DC) */
 PHP_SOLR_API void solr_string_appendc_ex(solr_string_t *dest, solr_char_t ch SOLR_MEM_DEBUG_DC)
 {
-	auto size_t __new_length = 0U;
+	size_t __new_length = 0U;
 
 	/* (Re)allocates memory and increases the capacity if necessary */
 	solr_string_alloc(dest, 1, &__new_length SOLR_MEM_DEBUG_CC);
@@ -101,8 +101,8 @@
 /* {{{ PHP_SOLR_API void solr_string_append_long(solr_string_t *dest, long int long_val) */
 PHP_SOLR_API void solr_string_append_long_ex(solr_string_t *dest, long int long_val SOLR_MEM_DEBUG_DC)
 {
-	auto size_t __new_length = 0U;
-	auto char tmp_buffer[SOLR_STRING_LONG_BUFFER_SIZE];
+	size_t __new_length = 0U;
+	char tmp_buffer[SOLR_STRING_LONG_BUFFER_SIZE];
 	size_t length = 0;
 
 	/* Write the formated long to the buffer */
@@ -127,8 +127,8 @@
 /* {{{ PHP_SOLR_API void solr_string_append_unsigned_long(solr_string_t *dest, unsigned long int long_val) */
 PHP_SOLR_API void solr_string_append_unsigned_long_ex(solr_string_t *dest, unsigned long int long_val SOLR_MEM_DEBUG_DC)
 {
-	auto size_t __new_length = 0U;
-	auto char tmp_buffer[SOLR_STRING_UNSIGNED_LONG_BUFFER_SIZE];
+	size_t __new_length = 0U;
+	char tmp_buffer[SOLR_STRING_UNSIGNED_LONG_BUFFER_SIZE];
 	size_t length = 0;
 
 	/* Write the formated unsigned long to the buffer */