It turns out #forceNewFileNamed: does not work either.

I believe the immediate cause of the problem is in the function you pointed me at: sqFileOpen() in platforms/Cross/plugins/FilePlugin/sqFilePluginBasicPrims.c:

	if (writeFlag) {
		/* First try to open an existing file read/write: */
		setFile(f, fopen(cFileName, "r+b"));
		if (getFile(f) == NULL) {
			/* Previous call fails if file does not exist. In that case,
			   try opening it in write mode to create a new, empty file.
			*/
			setFile(f, fopen(cFileName, "w+b"));
			if (getFile(f) != NULL) {
			    char type[4],creator[4];
				dir_GetMacFileTypeAndCreator(sqFileName, sqFileNameSize, type, creator);
				if (strncmp(type,"BINA",4) == 0 || strncmp(type,"????",4) == 0 || *(int *)type == 0 ) 
				    dir_SetMacFileTypeAndCreator(sqFileName, sqFileNameSize,"TEXT","R*ch");	
			}
		}

The first call to fopen() indeed fails if the file does not exist. But it also fails if the file exists but does not have both read and write "r+b" permission. So in that case the intent, as you mentioned, is to try to open in write-only but "w+b" is not the write-only mode, it is also a read and write mode, see [1]. So this fopen() attempt also fails if the file has write-only permission. A fix may be to use mode "wb" instead of "w+b", but I'm not sure if there are unintended consequences to doing this.

[1] http://en.wikibooks.org/wiki/C_Programming/C_Reference/stdio.h/fopen   

On May 31, 2014, at 14:45 , Douglas McPherson wrote:

> Ahh, thanks. I'll try it out when back in front of my machine.
> 
> Thanks,
> Doug
> 
> Sent from my iPhone
> 
> On May 31, 2014, at 14:23, Eliot Miranda <eliot.miranda at gmail.com> wrote:
> 
>> Hi Doug,
>> 
>> 
>> On Sat, May 31, 2014 at 10:00 AM, Douglas McPherson <djm1329 at san.rr.com> wrote:
>> Is there a way to open a write-only file in Squeak? On both Mac and Linux attempting to open such a file fails.
>> 
>> Squeak has forceNewFileNamed: & forceNewFileNamed:do:.  If you look at sqFileOpen in platforms/Cross/plugins/FilePlugin/sqFilePluginBasicPrims.c you'll see it first attempts to open read-write and if that fails, opens write-only.  So it should work.
>> 
>> HTH
>> 
>> For example, if you create a write-only file, i.e. in a shell, after cd to default directory
>> 
>> echo nada > foo
>> chmod 200 foo
>> 
>> Then from Squeak
>> 
>> StandardFileStream fileNamed: 'foo'
>> 
>> returns nil.
>> 
>> If the file is given read permission (i.e. chmod 600 foo) then Squeak can open it.
>> 
>> Anyone know a workaround?
>> 
>> Thanks,
>> Doug
>> 
>> 
>> -- 
>> best,
>> Eliot
>> 
> 

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