Category: DOS kernel
INT 21 - DOS 3.0+ - CREATE TEMPORARY FILE
AH = 5Ah
CX = file attribute (see #01420 at AX=4301h)
DS:DX -> ASCIZ path ending with a '\' + 13 zero bytes to receive the
generated filename
Return: CF clear if successful
AX = file handle opened for read/write in compatibility mode
DS:DX pathname extended with generated name for temporary file
CF set on error
AX = error code (03h,04h,05h) (see #01680)
Desc: creates a file with a unique name which must be explicitly deleted
Notes: under the FlashTek X-32 DOS extender, the path pointer is in DS:EDX
MS-DOS 3.0-4.0 and DR DOS 3.4-5.0 generate the filename as a sequence
of hex digits based on the current date and time; MS-DOS 6+,
DR DOS 6, and Novell DOS 7 use letters A-P in place of hex digits
MS-DOS 5.0 and DR DOS 3.41/5.0 will insert a missing trailing backslash
before appending the generated filename, but due to this, an empty
string results in a file in the root directory
BUGS: COMPAQ DOS 3.31 hangs if the pathname is at XXXXh:0000h; it apparently
wraps around to the end of the segment
MS-DOS 5.00 revisions A and B and PC-DOS 5.00 revision A reportedly
hang the system if the specified path is the root directory and the
root directory is full (no free directory entries)
Mark Incley <mincley@krisalis.demon.co.uk> reports that this function
hangs in MS-DOS 6.2x if the name includes two consecutive path
separators (e.g. C:\\ )
SeeAlso: AH=3Ch,AH=5Bh