From: Harold R. Zatz (hzatz@cco.caltech.edu)
Date: 08/02/92 

From: hzatz@cco.caltech.edu (Harold R. Zatz)
Subject: Re: Problems with extfs (a way to find the max file name length)
Date: Sun, 2 Aug 1992 21:44:21 GMT

        Actually, if all you're looking for is the maximum valid filename
length in a particular file system, why not just write a simple routine
that writes out a test file with an extremely large (>256) filename,
and then see how long a filename you can read back in?

        This works on my regular and msdos partitions; I don't have an
extfs partition to check it for. It does also work on my Apollo DN-10000
at work, though.

================================Cut here===========================
#include <stdio.h>
#include <sys/errno.h>

int getfilenamelen() {
        char name[1025];
        register i;
        FILE *file;

        for( i = 0 ; i < 1024 ; i++) name[i] = 'a';
        name[1024] = 0;

        for( i = 0 ; i < 1023 ; i++) {
                file = fopen( &(name[i]), "w" );
                if (!file && errno != ENAMETOOLONG && errno != ENOENT ) {
                        perror( "getfilenamelen" );
                        return -1; /* Error return */
                        }
                if (file) break;
                }
        fclose(file);

        for( ; i < 1023 ; i++) {
                file = fopen( &(name[i]), "r" );
                if (!file) break;
                fclose(file);
                }

        unlink( &(name[i]) );
        return 1025-i;
        }

main() {
        printf("Filename len is %d\n", getfilenamelen());
        exit(1);
        }
===============================Cut here===========================

        --Harold 

-- 
"Twas brillig and the slithy toves     I'm Harold R. Zatz, a.k.a. "H".   
Did gyre and gimble in the wabe;       Internet:  hzatz@graphics.cornell.edu
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