ref: dfea95b3c29ef4a6de2713a946453d3a022ae0b4
dir: /sys/src/ape/lib/fmt/werrstr.c/
#include <stdarg.h> #include <errno.h> #include "fmt.h" extern char *_plan9err; void werrstr(const char *fmt, ...) { va_list arg; va_start(arg, fmt); snprint(_plan9err, 128, fmt, arg); va_end(arg); errno = EPLAN9; }