tests/core/test_errar.c

#include <stdio.h>
#include <errno.h>
#include <string.h>

int main() {
  char* err;
  char buffer[200];

  err = strerror(EDOM);
  strerror_r(EWOULDBLOCK, buffer, 200);
  printf("<%s>\n", err);
  printf("<%s>\n", buffer);

  printf("<%d>\n", strerror_r(EWOULDBLOCK, buffer, 0));
  errno = 123;
  printf("<%d>\n", errno);

  return 0;
}