scc

commit b4bb95aaed9b85dc43d293e2c7310e81f0092005
parent 10686ff83b100fbf8f51b136fe5b351be6014226
Author: Roberto E. Vargas Caballero <k0ga@shike2.net>
Date:   Wed,  6 May 2026 21:07:48 +0200

libc/stdio: Use uinptr_t instead of -1 pointers

Using (char *)-1 - s should work in the majority of systems and
or compilers, but using uinptr_t and UINTPTR_MAX makes the code
cleaner and allows to remove the comment.

Diffstat:
M
src/libc/stdio/vsprintf.c
 | 
12
+++---------

1 file changed, 3 insertions(+), 9 deletions(-)
diff --git a/src/libc/stdio/vsprintf.c b/src/libc/stdio/vsprintf.c
@@ -7,13 +7,7 @@
 int
 vsprintf(char *restrict s, const char *restrict fmt, va_list va)
 {
-	/*
-	 * we used to use SIZE_MAX here, but that is just
-	 * wrong because we build a rp pointer that in that
-	 * case it is just wp - 1 by definition. As it
-	 * is impossible to span an object further than
-	 * the end of the memory space we can use the number
-	 * of bytes until the end of the address space.
-	 */
-	return vsnprintf(s, (char *)-1 - s, fmt, va);
+	uintptr_t addr = (uintptr_t) s;
+
+	return vsnprintf(s, UINTPTR_MAX - addr, fmt, va);
 }