.help zfxdir May84 "System Interface"
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NAME
zfxdir -- extract OS directory prefix from OSFN
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SYNOPSIS
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zfxdir (osfn, osdir, maxch, status)

char	osfn[ARB]		# OS filename
char	osdir[maxch]		# OS directory prefix
int	maxch, status
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DESCRIPTION
The OS directory prefix, if any, is extracted from the OS filename
and returned as \fIosdir\fR.
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RETURN VALUE
ERR is returned if the output string overflows.  If \fIosfn\fR is null
or does not contain a directory prefix a status of zero is returned,
otherwise the number of characters in the output string is returned.
If there is no directory prefix the null string is returned in \fIosdir\fR.
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NOTES
This routine is normally written in SPP since it does not communicate with
the host system.  Character string arguments are therefore not packed.
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SEE ALSO
zfpath, zfsubd, zfgcwd
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