/* Controller handle */ #if defined(__cplusplus) extern "C" { #endif typedef struct _MPIControl *MPIControl; #if defined(__cplusplus) } #endif
It means Code: #if defined(__cplusplus) extern "C" { #endif If __cplusplus is defined I declare the statement extern "C" { else Code: typedef struct _MPIControl *MPIControl; Code: #if defined(__cplusplus) } #endif If __cplusplus is defined I close the braces I opened before.