I am rebuilding a library that was last compiled a year ago using an earlier version of boost and an earlier version of Xcode (2.4) and an earlier version of Mac OS X (10.4). I downloaded boost_1_35_0 distro for my Mac and built it using the standard configuration and build procedures. That seemed to go OK. I am compiling C++ source code that formerly compiled, without errors or warnings, but now reports the following errors in many files: "error: 'snprintf' is not a member of 'std'" And, the offending line is the following from the c++locale.h file (the error is reported on the line referencing snprintf): #ifdef _GLIBCXX_USE_C99 const int __ret = std::snprintf(__out, __size, __fmt, __prec, __v); #else const int __ret = std::sprintf(__out, __fmt, __prec, __v); #endif Does anyone know the source of this problem. There is absolutely no changes in my source that is being compiled. I am dual posting this on both the boost-users and the Mac Xcode lists because I am not sure which is the more appropriate forum.