function new_from_fd(fd: Number(gint), writable: Boolean): GLib.MappedFile {
    // Gjs wrapper for g_mapped_file_new_from_fd()

Maps a file into memory. On UNIX, this is using the mmap() function.

If writable is true, the mapped buffer may be modified, otherwise it is an error to modify the mapped buffer. Modifications to the buffer are not visible to other processes mapping the same file, and are not written back to the file.

Note that modifications of the underlying file might affect the contents of the GLib.MappedFile. Therefore, mapping should only be used if the file will not be modified, or if all modifications of the file are done atomically (e.g. using GLib.file_set_contents).

Since 2.32


The file descriptor of the file to load


whether the mapping should be writable


a newly allocated GLib.MappedFile which must be unref'd with GLib.MappedFile.prototype.unref, or null if the mapping failed.