[fpc-devel] serial under linux, SerOpen blocks

[Armin Diehl]

Yes, found that a few minutes ago (strace is nice), micom does:

open("/dev/ttyUSB0", O_RDWR|O_NOCTTY|O_NONBLOCK) = 3
fcntl(3, F_GETFL)                       = 0x8802 (flags 
O_RDWR|O_NONBLOCK|O_LARGEFILE)
fcntl(3, F_SETFL, O_RDWR|O_LARGEFILE)   = 0
ioctl(3, SNDCTL_TMR_TIMEBASE or SNDRV_TIMER_IOCTL_NEXT_DEVICE or TCGETS, 
{B19200 -opost -isig -icanon -echo ...}) = 0
ioctl(3, TIOCMGET, [TIOCM_DTR|TIOCM_RTS]) = 0
ioctl(3, SNDCTL_TMR_TIMEBASE or SNDRV_TIMER_IOCTL_NEXT_DEVICE or TCGETS, 
{B19200 -opost -isig -icanon -echo ...}) = 0
ioctl(3, SNDCTL_TMR_START or SNDRV_TIMER_IOCTL_TREAD or TCSETS, {B19200 
-opost -isig -icanon -echo ...}) = 0
ioctl(3, SNDCTL_TMR_TIMEBASE or SNDRV_TIMER_IOCTL_NEXT_DEVICE or TCGETS, 
{B19200 -opost -isig -icanon -echo ...}) = 0
ioctl(3, TIOCMGET, [TIOCM_DTR|TIOCM_RTS]) = 0
ioctl(3, TIOCMSET, [TIOCM_DTR|TIOCM_RTS]) = 0
ioctl(3, SNDCTL_TMR_TIMEBASE or SNDRV_TIMER_IOCTL_NEXT_DEVICE or TCGETS, 
{B19200 -opost -isig -icanon -echo ...}) = 0
ioctl(3, SNDCTL_TMR_START or SNDRV_TIMER_IOCTL_TREAD or TCSETS, {B19200 
-opost -isig -icanon -echo ...}) = 0
ioctl(3, SNDCTL_TMR_TIMEBASE or SNDRV_TIMER_IOCTL_NEXT_DEVICE or TCGETS, 
{B19200 -opost -isig -icanon -echo ...}) = 0
ioctl(3, SNDCTL_TMR_TIMEBASE or SNDRV_TIMER_IOCTL_NEXT_DEVICE or TCGETS, 
{B19200 -opost -isig -icanon -echo ...}) = 0
ioctl(3, SNDCTL_TMR_START or SNDRV_TIMER_IOCTL_TREAD or TCSETS, {B19200 
-opost -isig -icanon -echo ...}) = 0
ioctl(3, SNDCTL_TMR_TIMEBASE or SNDRV_TIMER_IOCTL_NEXT_DEVICE or TCGETS, 
{B19200 -opost -isig -icanon -echo ...}) = 0
ioctl(3, SNDCTL_TMR_TIMEBASE or SNDRV_TIMER_IOCTL_NEXT_DEVICE or TCGETS, 
{B19200 -opost -isig -icanon -echo ...}) = 0
ioctl(3, SNDCTL_TMR_START or SNDRV_TIMER_IOCTL_TREAD or TCSETS, {B19200 
-opost -isig -icanon -echo ...}) = 0
ioctl(3, SNDCTL_TMR_TIMEBASE or SNDRV_TIMER_IOCTL_NEXT_DEVICE or TCGETS, 
{B19200 -opost -isig -icanon -echo ...}) = 0
ioctl(3, TCFLSH, 0x2)                   = 0

should that be changed in the standard serial.pp ?

On 08/18/2011 11:51 AM, Henry Vermaak wrote:
> On 18/08/11 10:34, Armin Diehl wrote:
>> Hi Peter,
>>
>> that is the same as in the standard serial.pp:
>>
>> Result := fpopen(DeviceName, O_RDWR or O_NOCTTY);
>>
>> and this fpopen will block as long as minicom is not started on that
>> device.
>
> Try to add O_NONBLOCK to the flags with fpopen.  Then set CLOCAL like 
> Peter suggested.  Then disable O_NONBLOCK again with fcntl if you want 
> blocking I/O back.
>
> Henry
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