Am 31.03.2023 um 02:12 schrieb Frank Swarbrick:
Because of the linkage pragma that specifies "OS" I imagine that, although the C code is
defined as "pass by value", the OS linkage overrides it to be passed by reference. Just
a guess; I don't have a C compiler.
this is true ... see my other post.
This means that _printf4 cannot by called by a "normal" C program,
if this #pragma linkage(...,OS) is not present at the caller's side
Maybe others have other impressions about the C implementation,
because they regularly use this #pragma linkage or because they use a
startup macro
which does it under the cover. We don't ...
I saw the "by value" behaviour which I described in detail, when I
looked almost every day
at dumps of C programs in the 1990s. It was crucial when debugging C
programs on the mainframe
at that time to be able to read the parameters which are passed between
C functions ... and there
were lots of functions passing there parameters by value. Internal C
functions, but they produced
normal save area chains, and it was no problem to walk thru the chains
and find the parameters
at every call level ...
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