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List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:232845 Archived-At: On 1/29/19 12:50 AM, Richard Stallman wrote: > > When doing that, please consider the scenario where argv[0] does not > > have a directory part (i.e., does not have a '/' in POSIX). In this case > > in the past it has been reasonably common for argv[0] to not identify > > the executable that would be found by searching PATH for a file with > > that name, either because PATH itself has changed since the parent did > > the search, or because the program is being executed in a chrooted jail, > > or for some other reason. If this usage need not be supported by GNU > > programs it would be helpful to have that clearly stated. > > The case exists, but is there anything to be said about it there? > I don't see anything. Perhaps you could write something like the following? Sometimes it is convenient for a program to determine the name of the file used to execute the program, in order to re-execute the program or to find other files near the executable file. In general argv[0] is not a reliable way to do this, as a program's invoker can set argv[0] to any string. In practice, if argv[0] contains a slash it normally names the executable; otherwise, for various reasons it might not name the executable even after searching through the directories named in the PATH environment variable. In any case if a program needs its installation location it is good practice to let the user specify it in some other way, such as via a command-line argument.