DOKK / manpages / debian 12 / libx11-doc / XVaCreateNestedList.3.en
XVaCreateNestedList(3) XLIB FUNCTIONS XVaCreateNestedList(3)

XVaCreateNestedList - allocate a nested variable argument list

typedef void * XVaNestedList;

XVaNestedList XVaCreateNestedList(int dummy, ...);

Specifies an unused argument (required by ANSI C).
...
Specifies the variable length argument list.

The XVaCreateNestedList function allocates memory and copies its arguments into a single list pointer, which may be used as a value for arguments requiring a list value. Any entries are copied as specified. Data passed by reference is not copied; the caller must ensure data remains valid for the lifetime of the nested list. The list should be freed using XFree when it is no longer needed.

Xlib - C Language X Interface

libX11 1.8.4 X Version 11