The
getbsize function determines the user's preferred block size based on the value of the “BLOCKSIZE” environment variable; see
environ(7) for details on its use and format.
The
getbsize function returns a pointer to a
NUL terminated string describing the block size, something like “1K-blocks”. If the
headerlenp parameter is not
NULL the memory referenced by
headerlenp is filled in with the length of the string (not including the terminating
NUL). If the
blocksizep parameter is not
NULL the memory referenced by
blocksizep is filled in with block size, in bytes.
If the user's block size is unreasonable, a warning message is written to standard error and the returned information reflects a block size of 512 bytes.