diff -r 98c90759f69e -r 5700ba9154ab src/printf.c
--- a/src/printf.c	Wed Feb 01 17:14:17 2023 +0100
+++ b/src/printf.c	Wed Feb 01 18:06:50 2023 +0100
@@ -31,9 +31,16 @@
 #include <stdio.h>
 #include <string.h>
 
-#define CX_PRINTF_BUFSIZE 256
+#ifndef CX_PRINTF_SBO_SIZE
+#define CX_PRINTF_SBO_SIZE 512
+#endif
 
-int cx_fprintf(void *stream, cx_write_func wfc, char const *fmt, ...) {
+int cx_fprintf(
+        void *stream,
+        cx_write_func wfc,
+        char const *fmt,
+        ...
+) {
     int ret;
     va_list ap;
     va_start(ap, fmt);
@@ -43,13 +50,13 @@
 }
 
 int cx_vfprintf(void *stream, cx_write_func wfc, char const *fmt, va_list ap) {
-    char buf[CX_PRINTF_BUFSIZE];
+    char buf[CX_PRINTF_SBO_SIZE];
     va_list ap2;
     va_copy(ap2, ap);
-    int ret = vsnprintf(buf, CX_PRINTF_BUFSIZE, fmt, ap);
+    int ret = vsnprintf(buf, CX_PRINTF_SBO_SIZE, fmt, ap);
     if (ret < 0) {
         return ret;
-    } else if (ret < CX_PRINTF_BUFSIZE) {
+    } else if (ret < CX_PRINTF_SBO_SIZE) {
         return (int) wfc(buf, 1, ret, stream);
     } else {
         int len = ret + 1;
@@ -80,11 +87,11 @@
     cxmutstr s;
     s.ptr = NULL;
     s.length = 0;
-    char buf[CX_PRINTF_BUFSIZE];
+    char buf[CX_PRINTF_SBO_SIZE];
     va_list ap2;
     va_copy(ap2, ap);
-    int ret = vsnprintf(buf, CX_PRINTF_BUFSIZE, fmt, ap);
-    if (ret > 0 && ret < CX_PRINTF_BUFSIZE) {
+    int ret = vsnprintf(buf, CX_PRINTF_SBO_SIZE, fmt, ap);
+    if (ret > 0 && ret < CX_PRINTF_SBO_SIZE) {
         s.ptr = cxMalloc(a, ret + 1);
         if (s.ptr) {
             s.length = (size_t) ret;