Function scan_varname

src/env.c:211–225

Return a pointer to the end of a valid ${VARNAME} string, or NULL. 'str' should point to the '$' character. First letter in VARNAME must be alpha or underscore, rest of letters are alnum or underscore. Any other character is an error. */

   rest of letters are alnum or underscore.
   Any other character is an error.  */
ATTRIBUTE_PURE
static char const *
scan_varname (char const *str)
{
  if (str[1] == '{' && (c_isalpha (str[2]) || str[2] == '_'))
    {
      char const *end = str + 3;
      while (c_isalnum (*end) || *end == '_')
        ++end;
      if (*end == '}')
        return end;
    }

  return NULL;
}

/* Return a pointer to a static buffer containing the VARNAME as
   extracted from a '${VARNAME}' string.