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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <syserr.h>
define RADIX 26
define SZ_SUFFIX 10
define NTRIES 5
define MAX_TRIP 5000
# MKTEMP -- Make a unique file name (used to generate temporary file names).
# Format of name is "seedNNNNcc.." where the seed is supplied by the caller,
# NNNN is (normally) the lowest four digits of the process id, and the
# characters "cc..." are the radix 26 representation of a local counter
# (maintained in static storage). The algorithm used virtually guarantees
# a unique name on the first try. Logical directory prefixes are allowed.
procedure mktemp (seed, temp_file, maxchars)
char seed[ARB], temp_file[ARB], suffix[SZ_SUFFIX]
int maxchars, counter, i, n, op, pid
int access(), itoc()
data counter/0/
begin
call zgtpid (pid) # get process id
do i = 1, MAX_TRIP {
call strcpy (seed, temp_file, maxchars)
op = itoc (mod(pid,10000), suffix, SZ_SUFFIX)
call strcat (suffix, temp_file, maxchars)
counter = counter + 1
op = 1
for (n=counter; n > 0; n = (n-1) / RADIX) {
suffix[op] = mod (n-1, RADIX) + 'a'
op = op + 1
}
suffix[op] = EOS
call strcat (suffix, temp_file, maxchars)
if (access (temp_file,0,0) == NO) # does file exist?
return
else if (mod(i,NTRIES) == 0)
pid = pid + mod(counter,10) # not likely to get here
}
call filerr (seed, SYS_FMKTEMP)
end
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