Bug 211949

This also effects the following webpage:

https://www.freebsd.org/doc/en/books/pmake/parellelism.html


I read the following paragraph and then printed the entire contents of 2.5 and had several other people read it and we all got the same general impression which I outline after displaying the paragraph in question:

*********************************************************************************

There are several problems you are likely to encounter. One is that some makefiles (and programs) are written in such a way that it is impossible for two targets to be made at once. The program xstr, for example, always modifies the files strings and x.c. There is no way to change it. Thus you cannot run two of them at once without something being trashed. Similarly, if you have commands in the makefile that always send output to the same file, you will not be able to make more than one target at once unless you change the file you use. You can, for instance, add a $$$$ to the end of the file name to tack on the process ID of the shell executing the command (each $$ expands to a single $, thus giving you the shell variable $$). Since only one shell is used for all the commands, you will get the same file name for each command in the script.

*********************************************************************************

I am guessing what is being conveyed (or at least seems to be) is not the intent for when the above is read it sounds like the following occurs:

1) That if you have a multiple commands that create/utilize a filename these can only be run 1 at a time otherwise they will step on each other -- understood

2) However a possible work around is to take on $$$$ to the end of the filename so that each file created gets its own unique Pid (or at least that is what it seems to imply anyway) -- aka here is a work around for the problem in item #1

3) However because PMake only operates under one shell the Pid will be the same for every process and as such all these filenames will still be the same.

Synopsis:  Here is a problem, here is a work-around to the problem, but the work-around to the problem will not work.

If this not what is trying to be conveyed then it needs to be reworded in a manner to clarify what it is trying to say -- on the other hand if this is what it is trying to convey I have to ask -- Why include it at all since it just creates confusion ??