These come from POSIX or similar platforms, or from the standard 'zic' implementation, but never got written down anywhere. * Theory: Document other POSIX-inspired restrictions on names. * zic.8 (DESCRIPTION): Document that zic's behavior is unspecified if some names are duplicates. Sometimes it complains, sometimes not. --- Theory | 10 ++++++++-- zic.8 | 3 +++ 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/Theory b/Theory index bd62c5c..b11cbc8 100644 --- a/Theory +++ b/Theory @@ -299,15 +299,21 @@ Here are the general rules used for choosing location names, in decreasing order of importance: Use only valid POSIX file name components (i.e., the parts of - names other than '/'). Within a file name component, + names other than '/'). Do not use the file name + components '.' and '..'. Within a file name component, use only ASCII letters, '.', '-' and '_'. Do not use digits, as that might create an ambiguity with POSIX TZ strings. A file name component must not exceed 14 characters or start with '-'. E.g., prefer 'Brunei' to 'Bandar_Seri_Begawan'. + A name must not be empty, or contain '//', or start or end with '/'. Do not use names that differ only in case. Although the reference - implementation is case-sensitive, some other implementations + implementation is case-sensitive, some other implementations are not, and they would mishandle names differing only in case. + If one name A is an initial prefix of another name AB (ignoring case), + then B must not start with '/', as a regular file cannot have + the same name as a directory in POSIX. For example, + 'America/New_York' precludes 'America/New_York/Bronx'. Uninhabited regions like the North Pole and Bouvet Island do not need locations, since local time is not defined there. If all the clocks in a region have agreed since 1970, diff --git a/zic.8 b/zic.8 index d61555e..d0d34ce 100644 --- a/zic.8 +++ b/zic.8 @@ -362,6 +362,9 @@ field is used as an alternate name for that zone. .PP Except for continuation lines, lines may appear in any order in the input. +However, the behavior is unspecified if multiple zone or link lines +define the same name, or if the source of one link line is the target +of another. .PP Lines in the file that describes leap seconds have the following form: .nf -- 1.8.1.2