C á Go Go

Calling out to C libraries from within Go is simple and supported as part of the standard distribution. Let's look at an example that wraps a user-land Dtrace library (libusdt). Included are things to keep in mind when dealing with C code.

Transcript

1. C á Go Go Wrap C libraries in Goodness
2. C á Go Go Wrap C libraries in Goodness (with a Dtrace example)
3. speaker.Who()
4. Go enthusiast
5. Go enthusiast who wanted to play with Dtrace in Go
6. talk.About()
7. You.
8. You & C libraries
9. So back to Dtrace
10. Dtrace fmt.Printf() on steroids Can track function calls and meanin ful information about those calls (usually ar uments) Dtrace probes can be put anywhere in your code (i.e. can live in userland) To create a Dtrace probe, import a C header
11. Dtrace Provider: has n probes, identified by two strin s: name and module Probe: has .Fire(), identified by two strin s: function and name; the parameters that .Fire() takes are defined when the probe is created
12. Code break
13. What’s the bi deal?
14. If we aren’t tracin , .Fire() is* a no-op. * our wrapper adds overhead
15. Dtrace probes are meant to live in your code, whether you’re debu in or not.
16. imported and not used: "fmt"
17. imported and not used: "fmt"
18. Other benefits omitted.
19. You & c o
20. c o http:// olan .or /cmd/c o/ Part of the standard Go distribution Enables the creation of Go packa es that call C code. Kinda ma ical.
21. /* #c o LDFLAGS: -lusdt -L/usr/local/lib #include <stdlib.h> #include "usdt.h" */ import "C"
22. All functions and structs in the C header files are now accessible from the C packa e
23. C.<C namespace>
24. Code break
25. Translation layer C.CStrin C.GoStrin C.GoBytes unsafe.Pointer
26. Keep in mind
27. C structures aren’t arba e collected defer C.free() to deallocated memory
28. Confi to compile C code can be dependent on environment
29. c o doesn’t handle static linkin yet
30. C code can call into Go code* http://code. oo le.com/p/ o-wiki/wiki/c o
31. Thank You @ecin : ithub.com/ecin/ o-dtrace