What does AGENT_LIB_API means?

[pannack]

Can anyone tell what does AGENT_LIB_API means?

[wsobel]

It's for Windows or *NIX when building shared libraries because you need to declare classes and external symbols as dllexport or visible.

The definitions are in config.h

#ifdef _WINDOWS
#define AGENT_SYMBOL_EXPORT __declspec(dllexport)
#define AGENT_SYMBOL_IMPORT __declspec(dllimport)
#else  // _WINDOWS
#define AGENT_SYMBOL_EXPORT __attribute__((visibility("default")))
#define AGENT_SYMBOL_IMPORT __attribute__((visibility("default")))
#endif  // _WINDOWS

#ifdef SHARED_AGENT_LIB

#ifdef AGENT_BUILD_SHARED_LIB
#define AGENT_LIB_API AGENT_SYMBOL_EXPORT
#else
#define AGENT_LIB_API AGENT_SYMBOL_IMPORT
#endif

#define AGENT_SYMBOL_VISIBLE AGENT_LIB_API

#else  // SHARED_AGENT_LIB

#define AGENT_LIB_API
#define AGENT_SYMBOL_VISIBLE

#endif

For Windows the DLL needs to export the symbols __declspec(dllexport) and any library using the shared library needs to import the symbols __declspec(dllimport). This macro defines AGENT_LIB_API as dllexport when AGENT_BUILD_SHARED_LIB is true (conan ... -o shared=True) and when included outside the dll, AGENT_BUILD_SHARED_LIB is not set, and therefore AGENT_LIB_API is dllimport.

On *NIX it makes sure we have all the symbols visible from anything using the shared library. The std way of doing this is to declare: __attribute__((visibility("default"))) for the shared symbol.

Both these techniques allow for only the API to be exported from the shared library and not every symbol.

Best,

• W