On Fri, 13 May 2005, Charles Geyer wrote:
Could Rvsnprintf (in src/main/errors.c) be added to the R API with prototype in include/R_ext/Print.h say?
Here's my problem. I'm trying to write some code that is not totally tied to R. Hence I want R style error messaging to be isolated in a small module. I do not want #include <R.h> and calls to error (Rf_error) in most of my code. Hence I want to write a module with something like
----- begin code snippet ----- #include <stdarg.h> #include <stdio.h> #include <R.h>
#define BUFSIZE 1024
void die(const char *format, ...) { char buf[BUFSIZE]; va_list arg;
va_start(arg, format); vsnprintf(buf, BUFSIZE, format, arg); va_end(arg); buf[BUFSIZE - 1] = '\0'; error(buf); } ----- end code snippet -----
But that's not portable because vsnprintf isn't. You've already made a big effort to work around nonportability of vsnprintf, but don't make it available in the API. Why not?
If I could change vsnprintf to Rvsnprintf above, then I wouldn't have to do some horrible autoconf song and dance that probably wouldn't be completely portable anyway.
Or is there a better solution I haven't seen?
R guarantees to have *vsnprintf* available. Putting things in the API is a one-way decision and ties our hands for ever. Rvsnprintf is not even exported from errors.c: it is static and just a convenience wrapper.
About all a user package needs to do is
AC_CHECK_DECLS([vsnprintf])
and in your code snippet
#if defined(HAVE_DECL_VSNPRINTF) && !HAVE_DECL_VSNPRINTF extern int vsnprintf (char *str, size_t count, const char *fmt, va_list arg); #endif
However, AFAIK all known R platforms do have vsnprintf these days: the MinGW compiler used on Windows gained it within the last year.
-- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595
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