Tandy 1000 Programmer's Reference Manual page 54

Chapter 1 I System Calls
DirSearchFirst
Search for First Entry
Function Call 1 l H
Searches the
disk
directory
for
the first name that matches the
filename in the FCB. The name can have the ? wildcard charac-
ter to match any character. To search for hidden or system files,
DS:DX must point to the first byte of the extended FCB prefix.
If a directory entry for the filename in the FCB is found, an un-
opened FCB of the same type (normal or extended) is created at
the Disk Transfer Address.
If an extended FCB is pointed to by DS:DX, the following search
pattern is used:
0
If the attribute byte (offset FCB-1) is zero, only normal file
entries are found. Entries for the volume label, subdirectories,
hidden files, and system files will not be returned.
If the attribute field is set for hidden or system files, or direc-
tory entries, it is considered an inclusive search. All normal
file entries plus all entries matching the specified attributes
are returned. To look at all directory entries except the vol-
ume label, the attribute byte can be set to hidden
+
system
+
directory (all 3 bits set).
0
If the attribute field is set for the volume label, it is consid-
ered an exclusive search, and only the volume label entry is
returned.
Entry Conditions:
AH
=
11H
DS:DX
=
pointer to the unopened FCB of the file for which to
search
E xi t Conditions
:
If AL
=
OOH, a directory entry was found.
If AL
=
FFH, no directory entry was found.
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