banan-os/userspace/test-framebuffer/main.cpp

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#include <fcntl.h>
#include <string.h>
#include <sys/framebuffer.h>
#include <sys/mman.h>
int main()
{
int fd = open("/dev/fb0", O_RDWR);
if (fd == -1)
{
perror("open");
return 1;
}
framebuffer_info_t fb_info;
if (pread(fd, &fb_info, sizeof(fb_info), -1) == -1)
{
perror("read");
return 1;
}
size_t fb_size = fb_info.width * fb_info.height * BANAN_FB_BPP / 8;
void* addr = mmap(nullptr, fb_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (addr == MAP_FAILED)
{
perror("mmap");
return 1;
}
memset(addr, 0xFF, fb_size);
if (msync(addr, fb_size, MS_SYNC) == -1)
{
perror("msync");
return 1;
}
sleep(4);
munmap(addr, fb_size);
close(fd);
return 0;
}