ggiResourceAcquire

Section: GGI (3)
Updated: 2006-12-30
Page Index

NAME

ggiResourceAcquire, ggiResourceRelease, ggiResourceMustAcquire : Acquire and release a LibGGI resource

SYNOPSIS

#include <ggi/ggi.h>

int ggiResourceAcquire(ggi_resource_t res, uint32_t actype);

int ggiResourceRelease(ggi_resource_t res);

int ggiResourceMustAcquire(ggi_resource_t res);

DESCRIPTION

ggiResourceAcquire acquires (locks) a LibGGI resource, typically a DirectBuffer (see examples below). The actype indicates the desired access type for the operation. The following flags may be bitwise-or'ed together:

GGI_ACTYPE_READ: read access to the resource
GGI_ACTYPE_WRITE: write access to the resource

ggiResourceRelease releases (unlocks) an already-acquired resource.

ggiResourceMustAcquire determines whether or not the specified resource needs to be acquired before using.

RETURN VALUE

ggiResourceAcquire and ggiResourceRelease return 0 on success, an ggi-error(3) code on failure.

ggiResourceMustAcquire is simply a macro that returns true if the resource must be explicitly acquired and released, or false if not. However, it is still safe to call ggiResourceAcquire or ggiResourceRelease even in the latter case; it would be a no-op.

EXAMPLES

Using DirectBuffers:

const ggi_directbuffer *dbuf;

/* Acquire DirectBuffer before we use it. */
if (ggiResourceAcquire(dbuf->resource, GGI_ACTYPE_WRITE) != 0) {
      fail("Error acquiring DirectBuffer\n");
}

/* Do framebuffer rendering here... */

/* Release DirectBuffer when done with it. */
ggiResourceRelease(dbuf->resource);