Entry

[Herman Rubin]

In article <15373 at rphroy.UUCP>, tkacik at rphroy.UUCP (Tom Tkacik) writes:

			..........................

> but my interpretation of it was to give the entry point into the program,
> if you did not like main.
> 
> Maybe something like:
> 
> entry start();
> 
> start()
> {
> 	/* this is now the main routine */
> }
> 
> Does anybody know what 'entry' was supposed to do?

An entry point in a program or subroutine was any point which could be
called from outside.  For example, it was standard for the function which
produced the sine or cosine to be of the form

sin(x)
.
.
.
entry cos(x)
.

which would tell the compiler that this was not a separate process, but that
cos was an entry point to the same process as sin.  The way that this is
usually handled in C is to use

sin(x)
.
.
return work(y)
cos(x)
.
.
return work(y)
work(y)
.
.
return expr

This always has two returns, whereas the other way would only have one,
although other manipulations may be needed.

The other use of entry, which is still available with difficulty, is to
tell the loader which globals are starting points, and which of them is
to be used,

These useful things seem to have been forgotten in the computing field.
Entry is not a pseudonym.
-- 
Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907
Phone: (317)494-6054
hrubin at l.cc.purdue.edu (Internet, bitnet, UUCP)