Replacement for vsscanf on msvc

Question

Hi, I've run into an issue porting a codebase from linux (gcc) to windows (msvc). It seems like the C99 function vsscanf isn't available and has no obvious replacement.

I've read about a solution using the internal function _input_l and linking statically to the crt runtime, but unfortunately I cannot link statically since it would mess with all the plugins (as dlls) being loaded by the application.

So is there any replacement or a way to write a wrapper for vsscanf?

Answer 1

A quick search turned up several suggestions, including http://www.flipcode.net/archives/vsscanf_for_Win32.shtml

Answer 2

A hack that should work:

int vsscanf(const char *s, const char *fmt, va_list ap)
{
  void *a[20];
  int i;
  for (i=0; i<sizeof(a)/sizeof(a[0]); i++) a[i] = va_arg(ap, void *);
  return sscanf(s, fmt, a[0], a[1], a[2], a[3], a[4], a[5], a[6], /* etc... */);
}

Replace 20 with the max number of args you think you might need. This code isn't terribly portable but it's only intended to be used on one particular broken system missing vsscanf so that shouldn't matter so much.

Answer 3

As this is tagged C++ have you considered just biting the bullet and moving away from the scanf line of functions completely? The C++ idiomatic way would be to use a std::istringstream. Rewriting to make use of that instead of looking for a vsscanf replacement would possibly be easier and more portable, not to mention having much greater type safety.