[lttng-docs.git] / contents / using-lttng / instrumenting / advanced-techniques / 32-bit-on-64-bit / building-instrumented-32-bit-c-application.md

---
id: building-instrumented-32-bit-c-application
---

Let us reuse the _Hello world_ example of
[Tracing your own user application](#doc-tracing-your-own-user-application)
([Getting started](#doc-getting-started) chapter).

The instrumentation process is unaltered.

First, a typical 64-bit build (assuming you're running a 64-bit system):

<pre class="term">
gcc -o hello64 -I. hello.c hello-tp.c -ldl -llttng-ust
</pre>

Now, a 32-bit build:

<pre class="term">
gcc -o hello32 -I. <strong>-m32</strong> hello.c hello-tp.c <strong>-L/usr/lib32</strong> \
    -ldl -llttng-ust <strong>-Wl,-rpath,/usr/lib32</strong>
</pre>

The `-rpath` option, passed to the linker, makes the dynamic loader
check for libraries in `/usr/lib32` before looking in its default paths,
where it should find the 32-bit version of `liblttng-ust`.
Commit	Line	Data
5e0cbfb0 PP	1	---
	2	id: building-instrumented-32-bit-c-application
	3	---
	4
	5	Let us reuse the _Hello world_ example of
	6	[Tracing your own user application](#doc-tracing-your-own-user-application)
	7	([Getting started](#doc-getting-started) chapter).
	8
	9	The instrumentation process is unaltered.
	10
	11	First, a typical 64-bit build (assuming you're running a 64-bit system):
	12
	13	<pre class="term">
	14	gcc -o hello64 -I. hello.c hello-tp.c -ldl -llttng-ust
	15	</pre>
	16
	17	Now, a 32-bit build:
	18
	19	<pre class="term">
	20	gcc -o hello32 -I. <strong>-m32</strong> hello.c hello-tp.c <strong>-L/usr/lib32</strong> \
	21	-ldl -llttng-ust <strong>-Wl,-rpath,/usr/lib32</strong>
	22	</pre>
	23
47bfcb75	24	The `-rpath` option, passed to the linker, makes the dynamic loader
5e0cbfb0 PP	25	check for libraries in `/usr/lib32` before looking in its default paths,
5e0cbfb0 PP	26	where it should find the 32-bit version of `liblttng-ust`.