> I have read the description of what INTERMEDIATE does at least a dozen times and I still don't really get it.
It took many reads, but I think I get it.
As a toy example, consider the dependency chain:
foo <- foo.o <- foo.c
^^^^^
`- candidate to be considered "intermediate"
Depending on how we wrote the rules, foo.o may automatically be considered "intermediate". If we didn't write the rules in a way that foo.o is automatically considered intermediate, we may explicitly mark it as intermediate by writing:
.INTERMEDIATE: foo.o
So, what does "foo.o" being "intermediate" mean? 2 things:
1. Make will automatically delete "foo.o" after "foo" has been built.
2. "foo.o" doesn't need to exist for "foo" to be considered up-to-date. If "foo" exists and is newer than "foo.c", and "foo.o" doesn't exist, "foo" is considered up-to-date (if "foo" was built by make, then when it was built, "foo.o" must have existed at the time, and must have been up-to-date with foo.c at the time). This is mostly a hack so that property #1 does not break incremental builds.
These seem like useful properties if disk space is at a premium, but is something that I have never wanted Make to do. Rather than characterizing it as "a hack on the fact the underlying model isn't rich enough", I'd characterize it as "a space-saving hack from a time when drives were smaller".
----
If, like me, you don't like this, and want to disable it even on files that Make automatically decides are intermediate, you can write:
.SECONDARY:
Which tells it 2 things:
a. never apply property #1; never automatically delete intermediate files
b. always apply property #2; always let us hop over missing elements in the dependency tree
I write .SECONDARY: for #a, and don't so much care for #b. But, because #1 never triggers, #b/#2 shoudn't ever come up in practice.
It took many reads, but I think I get it.
As a toy example, consider the dependency chain:
Depending on how we wrote the rules, foo.o may automatically be considered "intermediate". If we didn't write the rules in a way that foo.o is automatically considered intermediate, we may explicitly mark it as intermediate by writing: So, what does "foo.o" being "intermediate" mean? 2 things:1. Make will automatically delete "foo.o" after "foo" has been built.
2. "foo.o" doesn't need to exist for "foo" to be considered up-to-date. If "foo" exists and is newer than "foo.c", and "foo.o" doesn't exist, "foo" is considered up-to-date (if "foo" was built by make, then when it was built, "foo.o" must have existed at the time, and must have been up-to-date with foo.c at the time). This is mostly a hack so that property #1 does not break incremental builds.
These seem like useful properties if disk space is at a premium, but is something that I have never wanted Make to do. Rather than characterizing it as "a hack on the fact the underlying model isn't rich enough", I'd characterize it as "a space-saving hack from a time when drives were smaller".
----
If, like me, you don't like this, and want to disable it even on files that Make automatically decides are intermediate, you can write:
Which tells it 2 things:a. never apply property #1; never automatically delete intermediate files
b. always apply property #2; always let us hop over missing elements in the dependency tree
I write .SECONDARY: for #a, and don't so much care for #b. But, because #1 never triggers, #b/#2 shoudn't ever come up in practice.