Similar to the standard C
vsprintf() function but safer, since it
calculates the maximum space required and allocates memory to hold
the result. The returned string should be freed with
no longer needed.
The returned string is guaranteed to be non-NULL, unless
%ls conversions, which can fail if no multibyte
representation is available for the given character.
See also g_vasprintf(), which offers the same functionality, but additionally returns the length of the allocated string.
This function is not directly available to language bindings.
printf()format string, but notice [string precision pitfalls][string-precision]
The data is owned by the caller of the function. The value is a NUL terminated UTF-8 string.
The list of parameters to insert into the format string.