    MATCH_NULL_UNSET_VALUE 1513 libglibc/regex.c #define MATCH_NULL_UNSET_VALUE 3
    MATCH_NULL_UNSET_VALUE 4046 libglibc/regex.c       REG_MATCH_NULL_STRING_P (reg_info[mcnt]) = MATCH_NULL_UNSET_VALUE;
    MATCH_NULL_UNSET_VALUE 4374 libglibc/regex.c           if (REG_MATCH_NULL_STRING_P (reg_info[*p]) == MATCH_NULL_UNSET_VALUE)
    MATCH_NULL_UNSET_VALUE 5437 libglibc/regex.c       if (REG_MATCH_NULL_STRING_P (reg_info[reg_no]) == MATCH_NULL_UNSET_VALUE)