printf/vprintf

In addition to FMDEBUG logging, FM SDK 5.0 introduces support for the C standard printf() and vprintf()  functions. These functions can be called at any time, with or without the debug library, and accept all standard C99 formatting specifiers. 

In FMs, these functions do not print to stdout, but instead send log messages to the hsmtrace log. Since these are formatting messages for a log rather than stdout, there are two differences from the standard C implementations.

Each line of output from printf()/vprintf() is prefixed with a log header that includes the FM’s id.