Re: Importing C extern errno into HP-UX assembler

Super! The resulting assembler listing showed me how to fix up my
assembler subroutine.

Thanks!

Mike


Paul Pluzhnikov wrote:
marnol01@xxxxxxxxxxxx writes:

I have tried many various .IMPORT statements and intsructions
to import the C extern errno variable into a PA-RISC assembler
procedure in order to modify errno from the assembler program.
So far, everything I've tried either has no effect or causes
the program to crash. This is for a PA-RISC 1.1 architecture.
I have a main.c where errno is defined with errno.h, and the
assembler subroutine which needs to be able to modify errno.
I assemble the procedure into a .o file, then use cc to compile
main.c and link it to the .o file. Does anyone have a fully
detailed example of what I need to do to accomplish this?

Compile the following code to assembly (with 'cc -S t.c'):

#include <errno.h>
void foo() { errno = 42; }

The resulting assembly is *exactly* what you need.
The proof:

$ cat t1.c
#include <errno.h>
int main()
{
foo();
printf("%d\n", errno);
return 0;
}

$ cc -S t.c && cc -c t.s && cc t1.c t.o && ./a.out
42

Cheers,
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