sprint.c (1373B)
1 /* 2 * The authors of this software are Rob Pike and Ken Thompson. 3 * Copyright (c) 2002 by Lucent Technologies. 4 * Permission to use, copy, modify, and distribute this software for any 5 * purpose without fee is hereby granted, provided that this entire notice 6 * is included in all copies of any software which is or includes a copy 7 * or modification of this software and in all copies of the supporting 8 * documentation for such software. 9 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED 10 * WARRANTY. IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE 11 * ANY REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY 12 * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE. 13 */ 14 #include <stdarg.h> 15 #include "plan9.h" 16 #include "fmtdef.h" 17 18 int 19 sprint(char *buf, const char *fmt, ...) 20 { 21 int n; 22 uint len; 23 va_list args; 24 25 len = 1<<30; /* big number, but sprint is deprecated anyway */ 26 /* 27 * on PowerPC, the stack is near the top of memory, so 28 * we must be sure not to overflow a 32-bit pointer. 29 * 30 * careful! gcc-4.2 assumes buf+len < buf can never be true and 31 * optimizes the test away. casting to uintptr works around this bug. 32 */ 33 if((uintptr_t)buf+len < (uintptr_t)buf) 34 len = -(uintptr_t)buf-1; 35 36 va_start(args, fmt); 37 n = vsnprint(buf, len, fmt, args); 38 va_end(args); 39 return n; 40 }