// filename:c2011-7-1-4-ex.c
// original examples and/or notes:
// 		(c) ISO/IEC JTC1 SC22 WG14 N1570, April 12, 2011
// 			C2011 7.1.4 Use of library functions
// compile and output mechanism:
// 		(c) Ogawa Kiyoshi, kaizen@gifu-u.ac.jp, December.29, 2013
// compile errors and/or wornings:
// 		(c) Apple LLVM version 4.2 (clang-425.0.27) (based on LLVM 3.2svn)
// 			Target: x86_64-apple-darwin11.4.2 //Thread model: posix
// 		(c) LLVM 2003-2009 University of Illinois at Urbana-Champaign.
#include <stdio.h>
#include <math.h> 
// note 163)

#define abs(x) _BUILTIN_abs(x)
#undef abs
int i;
// Example
#include <stdlib.h>
const char *str;
/* ... */
void f(void){
i = atoi(str);

//#include <stdlib.h>
#undef atoi
//const char *str;
/* ... */
i = atoi(str);

//#include <stdlib.h>
//const char *str;
/* ... */
i = (atoi)(str);

extern int atoi(const char *);
//const char *str;
/* ... */
i = atoi(str);
}
int main(void)
{
return printf("7.1.4 Use of library functions %d\n",abs(-3));	
}
// output may be
// 7.1.4 Use of library functions 3