9base

revived minimalist port of Plan 9 userland to Unix
git clone git://git.suckless.org/9base
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sprint.c (707B)

      1 /* Copyright (c) 2002-2006 Lucent Technologies; see LICENSE */
      2 #include <stdarg.h>
      3 #include <fmt.h>
      4 #include "plan9.h"
      5 #include "fmt.h"
      6 #include "fmtdef.h"
      7 
      8 int
      9 sprint(char *buf, char *fmt, ...)
     10 {
     11 	int n;
     12 	uint len;
     13 	va_list args;
     14 
     15 	len = 1<<30;  /* big number, but sprint is deprecated anyway */
     16 	/*
     17 	 * on PowerPC, the stack is near the top of memory, so
     18 	 * we must be sure not to overflow a 32-bit pointer.
     19 	 *
     20 	 * careful!  gcc-4.2 assumes buf+len < buf can never be true and
     21 	 * optimizes the test away.  casting to uintptr works around this bug.
     22 	 */
     23 	if((uintptr)buf+len < (uintptr)buf)
     24 		len = -(uintptr)buf-1;
     25 
     26 	va_start(args, fmt);
     27 	n = vsnprint(buf, len, fmt, args);
     28 	va_end(args);
     29 	return n;
     30 }