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#define XERR
#include "mmapbuf.ih"
void MmapBuf::mapBuffer(int protection)
{
int fd = open(d_fname.c_str(),
protection == PROT_READ ? O_RDONLY : O_RDWR
);
if (fd == -1) // file can't be opened
failure("can't open " + d_fname);
// mmap and munmap accept buffers for reading exceeding the file size
d_buffer = static_cast<char *>( // mmap the required buffer
mmap(0, d_bufSize, protection, MAP_SHARED, fd, d_offset)
);
close(fd);
if (d_buffer == MAP_FAILED) // mapping failed
failure("mmap for " + d_fname + " failed");
d_maxPtr = d_buffer;
}
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