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diff --git a/unix/os/doc/zfsubd.hlp b/unix/os/doc/zfsubd.hlp new file mode 100644 index 00000000..1e58f36b --- /dev/null +++ b/unix/os/doc/zfsubd.hlp @@ -0,0 +1,76 @@ +.help zfsubd May84 "System Interface" +.ih +NAME +zfsubd -- get host name of a subdirectory +.ih +SYNOPSIS +.nf +zfsubd (osdir, subdir, new_osdir, maxch, nchars) + +char osdir[ARB] # directory pathname +char subdir[ARB] # subdirectory of osdir +char new_osdir[maxch] # pathname of osdir/subdir +int maxch # maximum length of new_osdir +int nchars # length of new_osdir +.fi +.ih +DESCRIPTION +Given \fIosdir\fR, the machine dependent name of a host directory, +and \fIsubdir\fR, the filename of a subdirectory of \fIosdir\fR, \fBzfsubd\fR +returns the machine dependent name of the subdirectory. +The machine dependent directory specification \fInew_osdir\fR may be +concatenated with a filename to produce an OSFN, or may be used in another +call to \fBzfsubd\fR to generate the name of a directory lower in the hierarchy. + +If \fIosdir\fR is null the current working directory is assumed. +If \fIsubdir\fR is null or has the value "." \fIosdir\fR is either copied to +the output or modified as necessary to return a concatenatable directory +prefix string. If \fIsubdir\fR has the value ".." the name of the next +\fIhigher\fR directory is returned, i.e., the directory in which \fIosdir\fR +appears as a subdirectory. +.ih +RETURN VALUE +ERR is returned if the translation cannot be performed (but the existence of +the new directory is not checked). If the translation is successful the number +of characters in the string \fInew_osdir\fR is returned, excluding the EOS +delimiter. +.ih +NOTES +This primitive is used by FIO to convert subdirectory references in virtual +filenames into machine dependent directory specifications. +An arbitrary virtual pathname is translated by repeatedly calling \fBzfsubd\fR +to add successive / delimited subdirectory names into the OS directory name. +The new OS directory name is not necessarily an absolute pathname; on some +systems it may be a pathname relative to the current directory. If an absolute +pathname is desired an additional call should be made to \fBzfpath\fR to +convert \fInew_osdir\fR into an absolute pathname. +This primitive is normally coded in SPP hence all strings are normal SPP +character strings rather than packed Fortran strings. +.ih +EXAMPLE +Consider the following VFN: + + pkg$images/imdelete.x + +The logical directory "pkg" is defined in the environment as "iraf$pkg/". +Assume the host system is VMS and "iraf", the root directory of the IRAF +system, is defined as "dra0:[iraf]". Recursive expansion of logical +directories will result in the following virtual pathname: + + dra0:[iraf]pkg/images/imdelete.x + +FIO will next call \fBzfxdir\fR to extract the OSDIR "dra0:[iraf]", +followed by \fBzfsubd\fR to combine this OSDIR and the subdirectory +name "pkg" to produce the new OSDIR "dra0:[iraf.pkg]". The process is +repeated until the final OSFN is generated: + + dra0:[iraf.pkg.images]imdelete.x +.ih +BUGS +We assume that an OSFN can be generated by a simple concatenation of an OS +directory specification and a filename. This assumption is valid on all +systems we are familiar with, but may be false on some unfamiliar host. +.ih +SEE ALSO +zfxdir, zfpath +.endhelp |