Join MDN and developers like you at Mozilla's View Source conference, 12-14 September in Berlin, Germany. Learn more at


Defines the signature of the function a client must implement.


#include <prinit.h>

typedef PRStatus (PR_CALLBACK *PRCallOnceFN)(void);


The function is called to perform the initialization desired. The function is expected to return a PRStatus indicating the outcome of the process.

Document Tags and Contributors

 Contributors to this page: teoli, Rappo
 Last updated by: teoli,