[squeak-dev] FFI and capturing external program input in Squeak/Pharo

Dave Mason dmason at mason-rose.ca
Fri Jun 17 16:34:10 UTC 2011

I'm working on making a clean interface layer on top of FFI (and  
possibly Alien and NativeBoost).

It will look something like:

	FFIParse createFFI: #System category: 'My-Category' library: 'System'.
	System parseSystemHeader: 'sys/resource.h'.
	rusage := System struct: #rusage.
	System getrusage: 0 with: rusage.
	Transcript show: 'Used ';
			 show: rusage ru_utime tv_sec;
			 show: '.';
			 show: rusage ru_utime tv_usec;
			 show: ' seconds of user CPU time';
	System parseSystemHeaer: 'unistd.h';
		sleep: 5.
	pid := System getpid

I have a very compact, almost compete C header parser but I need to be  
able to get the output from
	popen("echo \"#include <unistd.h>\"|gcc -E -","r")
or equivalent.  The popen is easy enough to get at through FFI, but is  
there a way to connect either the FILE* or the file descriptor up to  
some ReadStream.  In the worst case, I could probably use FFI to call  
fread(3) but is there a better way?

I'd also appreciate any simple examples of using FFI, especially with  
ExternalStructure subclasses.

Finally is there a way to get external variables such as 'extern int  
errno;' ?

Thanks in advance!


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