- 1 year ago
C++ - I need a macro or an environment variable to detect when I am doing bazel run on Windows
In Bazel, you can use Bazel's built-in PLATFORM
and WINDOWS
variables to detect when you are running on Windows. Bazel provides a set of predefined environment variables that you can use in build rules and macros to make platform-specific decisions.
To detect if you are running on Windows, you can use the WINDOWS
variable, which is a boolean variable that evaluates to 1
if the platform is Windows and 0
otherwise.
Here's an example of how to use the WINDOWS
variable in a Bazel build rule:
pythoncc_binary(
name = "my_binary",
srcs = ["main.cc"],
copts = select({
"//conditions:default": [],
"//conditions:windows": ["/DWINDOWS"],
}),
)
In the example above, the cc_binary
rule has a copts
attribute, which is used to specify compiler options. The select
function allows you to conditionally set compiler options based on the platform.
The //conditions:default
label represents the default case for non-Windows platforms, and //conditions:windows
represents the case for Windows. In the Windows case, we add the /DWINDOWS
option to define the WINDOWS
preprocessor macro.
Now, in your C++ code, you can use the #ifdef
directive to check for the presence of the WINDOWS
macro:
cpp#include <iostream>
int main() {
#ifdef WINDOWS
std::cout << "Running on Windows" << std::endl;
#else
std::cout << "Not running on Windows" << std::endl;
#endif
return 0;
}
When you run bazel run my_binary
, it will print "Running on Windows" if you are running on a Windows platform and "Not running on Windows" otherwise.
This way, you can use the WINDOWS
variable in Bazel to detect if you are doing a bazel run
on Windows and perform platform-specific actions or configurations accordingly.