Preloading a version that alternates between two buffers is clearly Wrong, but I'm not sure what the right solution is - do you/does anyone have a pattern that

Preloading a version that alternates between two buffers is clearly Wrong, but I'm not sure what the right solution is - do you/does anyone have a pattern that they find works well for them? Our codebase has quite a few functions like inet_ntoa(): /* returns ptr. to internal static storage */ const char *type_to_str(const Type *type); You could pass an explicit argument, but that's pretty ugly: /* Explicit buffer argument */ char msg_buf1[256], msg_buf2[256], msg_buf3[256], ..., msg_buf16[256]; char *type_to_str(char *buf_to_use, size_t buf_size, const Type *type) Alternatively, you could give C99 a workout and abuse compound literals as anonymous storage: #include <stdio.h> struct foo { int bar; }; #define FOO_TO_STR_SIZE 256 #define foo_to_str(foo) \ foo_to_str_((char [FOO_TO_STR_SIZE]){ 0 }, FOO_TO_STR_SIZE, (foo)) /* Implementation detail */ __attribute__((nonnull)) static char *foo_to_str_(char *buf_to_use, size_t size, const struct foo *foo) { (void)snprintf(buf_to_use, size, "%d", foo->bar); return buf_to_use; } int main(void) { const struct foo foo = { .bar = 42 }, foo2 = { .bar = 43 }; printf("%s %s\n", foo_to_str(&foo), foo_to_str(&foo2)); return 0; } (Warning: this is probably too clever. Note that you need the explicit size argument if you offer a library, or you risk your callers using a different FOO_TO_STR_SIZE than you do. There is probably a very minor performance penalty to this solution as the caller must, in general, completely initialize the string. Note the gcc warnings about compound literals in C++ - see https://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html https://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html for a discussion.)