The functions vscanf and friends are provided so that you can
define your own variadic scanf-like functions that make use of
the same internals as the built-in formatted output functions.
These functions are analogous to the vprintf series of output
functions. See Variable Arguments Output, for important
information on how to use them.
Portability Note: The functions listed in this section were introduced in ISO C99 and were before available as GNU extensions.
This function is similar to
scanf, but instead of taking a variable number of arguments directly, it takes an argument list pointer ap of typeva_list(see Variadic Functions).
This function is similar to
wscanf, but instead of taking a variable number of arguments directly, it takes an argument list pointer ap of typeva_list(see Variadic Functions).
This is the equivalent of
fscanfwith the variable argument list specified directly as forvscanf.
This is the equivalent of
fwscanfwith the variable argument list specified directly as forvwscanf.
This is the equivalent of
sscanfwith the variable argument list specified directly as forvscanf.
This is the equivalent of
swscanfwith the variable argument list specified directly as forvwscanf.
In GNU C, there is a special construct you can use to let the compiler
know that a function uses a scanf-style format string. Then it
can check the number and types of arguments in each call to the
function, and warn you when they do not match the format string.
For details, see Declaring Attributes of Functions.