"TRACEPOINT_DEFINE" and include the tracepoint provider.
- Use "-I." for the compilation unit containing the tracepoint
provider include (e.g. tp.c).
- - Link application with "-ldl -llttng-ust".
+ - Link application with "-ldl" on Linux, with "-lc" on BSD.
+ - If building the provider directly into the application,
+ link the application with "-llttng-ust".
+ - If building a static library for the provider, link the static
+ library with "-lllttng-ust".
- Include the tracepoint provider header into all C files using
the provider.
- Example:
- tests/hello/ hello.c tp.c ust_tests_hello.h Makefile.example
+ tests/hello/ hello.c tp.c ust_tests_hello.h Makefile.example.*
2) Compile the Tracepoint Provider separately from the application,
using dynamic linking:
files that use the provider.
- Compile the tracepoint provider with "-I.".
- Link the tracepoint provider with "-llttng-ust".
- - Link application with "-ldl".
+ - Link application with "-ldl" on Linux, "-lc" on BSD.
- Set a LD_PRELOAD environment to preload the tracepoint provider
shared object before starting the application when tracing is
- needed.
+ needed. Another way is to dlopen the tracepoint probe when needed
+ by the application.
- Example:
- tests/demo/ demo.c tp*.c ust_tests_demo*.h demo-trace
- - Note about dlopen() usage: due to locking side-effects due to the
- way libc lazily resolves Thread-Local Storage (TLS) symbols when a
- library is dlopen'd, linking the tracepoint probe or liblttng-ust
- with dlopen() is discouraged. They should be linked with the
- application using "-llibname" or loaded with LD_PRELOAD.
- Enable instrumentation and control tracing with the "lttng" command
from lttng-tools. See lttng-tools doc/quickstart.txt.
- tests
Various test programs
- - liblttng-ust-libc
+ - liblttng-ust-libc-wrapper
An example library that can be LD_PRELOAD'ed to instrument some
calls to libc (currently malloc() and free()) in any program without
need to recompile it.