vrb_resize(3) create a new virtual ring buffer




#include <vrb.h>

vrb_p vrb_resize(size_t size, const char *name);


vrb_resize changes the size of a virtual ring buffer if the data in the source buffer will fit in the requested space.


vrb_p vrb
specifies the ring buffer which will be resized.

size_t size
specifies the requested minimum buffer size to be allocated. The given value will be rounded up to the nearest or equal whole multiple of the system page size. The virtual ring buffer is implemented by mapping two adjacent blocks of memory to the same memory object. Thus, twice as much virtual address space will be used and the specified size must be less than half of the available virtual address space for this process.

const char *name
specifies an optional name of a file to be used as backing store via mmap(2) in a mounted filesystem in which the process has write permission. If the named file cannot be opened for write, an error will occur. If NULL is given, swap space will be used as backing store via shmat(2).


On success, 0 is returned. Otherwise, -1 is returned.


If an error is returned, then errno will have one of the following values:
The data in the current virtual ring buffer will not fit into the requested space.
A buffer size was requested which is too large for address space allocation arithmetic.
Out of memory allocating the virtual ring buffer structure.
An errno value set by a failing system call.