PVS-Studio warning V528 for Scilab

int sci_xcosPalLoad(char *fname, unsigned long fname_len)
{
  ....
  char **category = NULL;
  ....
  if (category == NULL ||
      (lenCategory == 1 && *category == '\0'))
  ....
}

This suspicious code was found in Scilab project by PVS-Studio static code analyzer.
Warning message is:
V528 It is odd that pointer to 'char' type is compared with the '\0' value. Probably meant: ** category == '\0'. sci_xcospalload.cpp 57

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