[En-Nut-Discussion] unblocking get char
bon at elektron.ikp.physik.tu-darmstadt.de
Thu Oct 11 11:00:53 CEST 2012
>>>>> "Ole" == Ole Reinhardt <ole.reinhardt at embedded-it.de> writes:
Ole> Hi Ayman,
>> I need to add a function that not locking until the user input char
>> through standard input, by another meaning using getchar(); function
>> will lock the thread until the user enter a char, I need the opposite
>> that if the user was keep pressing a certain char, it will get that
>> char if not, the execution will keep running without any blocking.
Ole> Please read http://www.ethernut.de/nutwiki/Advanced_UART_Functions,
Ole> especially the chapter about read timeouts.
Ole> You can set a timeout until which the read functions (and getchar
Ole> is only one of them) will return an error code instead of the char.
Ole> Btw: Nut/OS uses more or less the same behaviour like other POSIX
Ole> c-lib implementations.
But timeout is in Milliseconds. And '0' means infinite wait. So you have to
specify at least '1' . And that can mean a blocking behaviour for up to 1
Millisecond. Does perhaps have 0xffffffff ('-1') have another special
meaning, as to _not_ wait at all. Would that be usefull?
Uwe Bonnes bon at elektron.ikp.physik.tu-darmstadt.de
Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------
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