The _aaaa_iiii_oooo______rrrr_eeee_aaaa_dddd_((((_)))) function allows the calling process to read aaaaiiiiooooccccbbbbpppp----
>>>>aaaaiiiioooo____nnnnbbbbyyyytttteeeessss from the file associated with aaaaiiiiooooccccbbbbpppp---->>>>aaaaiiiioooo____ffffiiiillllddddeeeessss into the
buffer pointed to by aaaaiiiiooooccccbbbbpppp---->>>>aaaaiiiioooo____bbbbuuuuffff (see rrrreeeeaaaadddd((((2222))))). The function call
returns when the read request has been initiated or, at a minimum, queued
for the file or device.
The aaaaiiiiooooccccbbbb---->>>>aaaaiiiioooo____ssssiiiiggggeeeevvvveeeennnntttt defines how the calling process will be notified
upon I/O completion.
If ssssiiiiggggeeeevvvv____nnnnoooottttiiiiffffyyyy is SSSSIIIIGGGGEEEEVVVV____NNNNOOOONNNNEEEE, then no notification will be posted to the
calling application.
If ssssiiiiggggeeeevvvv____nnnnoooottttiiiiffffyyyy is SSSSIIIIGGGGEEEEVVVV____SSSSIIIIGGGGNNNNAAAALLLL, then the signal specified in ssssiiiiggggeeeevvvv____ssssiiiiggggnnnnoooo
will be sent to the calling process. If SSSSAAAA____SSSSIIIIGGGGIIIINNNNFFFFOOOO is set for the signal
(see ssssiiiiggggaaaaccccttttiiiioooonnnn((((2222))))) and the signal is in the range of SSSSIIIIGGGGRRRRTTTTMMMMIIIINNNN and
SSSSIIIIGGGGRRRRTTTTMMMMAAAAXXXX then the signal will be queued to the process and the value in
ssssiiiiggggeeeevvvv____vvvvaaaalllluuuueeee will be the ssssiiii____vvvvaaaalllluuuueeee in the generated signal.
If ssssiiiiggggeeeevvvv____nnnnoooottttiiiiffffyyyy is SSSSIIIIGGGGEEEEVVVV____CCCCAAAALLLLLLLLBBBBAAAACCCCKKKK then the function ssssiiiiggggeeeevvvv____ffffuuuunnnncccc will be
called with ssssiiiiggggeeeevvvv____vvvvaaaalllluuuueeee as the argument. Only one callback will be called
at a time, however programs should be careful to note that a callback may
be run in parallel with the calling process.
If ssssiiiiggggeeeevvvv____nnnnoooottttiiiiffffyyyy is SSSSIIIIGGGGEEEEVVVV____TTTTHHHHRRRREEEEAAAADDDD then the function ssssiiiiggggeeeevvvv____nnnnoooottttiiiiffffyyyy____ffffuuuunnnnccccttttiiiioooonnnn
will be called by a new thread (see pppptttthhhhrrrreeeeaaaaddddssss((((5555))))) with ssssiiiiggggeeeevvvv____vvvvaaaalllluuuueeee as the
argument. This thread is created when the event arrives with the
attributes specified in ssssiiiiggggeeeevvvv____nnnnoooottttiiiiffffyyyy____aaaattttttttrrrriiiibbbbuuuutttteeeessss except that it is
automatically detached. The calling process should ensure there are
sufficient resources to create the thread.
All aaaaiiiioooo____rrrreeeeaaaadddd(((()))) calls must supply a complete aaaaiiiiooooccccbbbb---->>>>aaaaiiiioooo____ssssiiiiggggeeeevvvveeeennnntttt
structure.
The aaaaiiiiooooccccbbbbpppp---->>>>aaaaiiiioooo____lllliiiioooo____ooooppppccccooooddddeeee field is ignored by aaaaiiiioooo____rrrreeeeaaaadddd(((()))).
Prioritized I/O is not currently supported among asynchronous file
operations. aaaaiiiiooooccccbbbbpppp---->>>>aaaaiiiioooo____rrrreeeeqqqqpppprrrriiiioooo must be set to 0, otherwise the call