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Clarified the meaning of 0x0 and 0x30 signal handlers

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This commit is contained in:
Thomas Schmitt 2010-08-28 11:29:29 +00:00
parent cf7966db44
commit 54c1631e92
1 changed files with 24 additions and 18 deletions
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42
libburn/trunk/test/libburner.c
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@ -20,31 +20,37 @@
Before you can do anything, you have to initialize libburn by
burn_initialize()
and provide some signal and abort handling, e.g. by the builtin handler, by
burn_set_signal_handling()
as it is done in main() at the end of this file. Then you aquire a
drive in an appropriate way conforming to the API. The two main
approaches are shown here in application functions:
burn_set_signal_handling("libburner : ", NULL, 0x0)
as it is done in main() at the end of this file.
Then you aquire a drive in an appropriate way conforming to the API. The twoi
main approaches are shown here in application functions:
libburner_aquire_by_adr() demonstrates usage as of cdrecord traditions
libburner_aquire_by_driveno() demonstrates a scan-and-choose approach
With that aquired drive you can blank a CD-RW or DVD-RW
With that aquired drive you can blank a CD-RW or DVD-RW as shown in
libburner_blank_disc()
or you can format a DVD-RW to profile "Restricted Overwrite" (needed once)
or an unused BD to default size with spare blocks
libburner_format()
With the aquired drive you can burn to CD, DVD, BD
With the aquired drive you can burn to CD, DVD, BD. See
libburner_payload()
These three functions switch temporarily to a non-fatal signal handler
while they are waiting for the drive to become idle again:
burn_set_signal_handling("libburner : ", NULL, 0x30)
After the waiting loop ended, they check for eventual abort events by
burn_is_aborting(0)
The 0x30 handler will eventually execute
burn_abort()
but not wait for the drive to become idle and not call exit().
This is needed because the worker threads might block as long as the signal
handler has not returned. The 0x0 handler would wait for them to finish.
Take this into respect when implementing own signal handlers.
When everything is done, main() releases the drive and shuts down libburn:
burn_drive_release();
burn_finish()
FreeBSD does not work well with the convenient synchronous signal handler. So
the waiting loops for blanking, formatting, and writing use the asynchronous
mode of the libburn signal handler. It will not shutdown the library and
abort the program, but rather tell the ongoing drive operation to stop as
soon as possible. After the loops and at the end of the program there is a
call to determine whether an abort happened:
burn_is_aborting()
Applications must use 64 bit off_t. E.g. by defining
#define _LARGEFILE_SOURCE
#define _FILE_OFFSET_BITS 64
@ -60,7 +66,7 @@
/* This program insists in the own headerfile. */
#include "../libburn/libburn.h"
/* libburn is intended for Linux systems with kernel 2.4 or 2.6 for now */
/* libburn works on Linux systems with kernel 2.4 or 2.6, FreeBSD, Solaris */
#include <stdio.h>
#include <ctype.h>
#include <sys/types.h>
@ -333,7 +339,7 @@ int libburner_blank_disc(struct burn_drive *drive, int blank_fast)
if (burn_is_aborting(0) > 0)
return -1;
/* Back to synchronous handling */
burn_set_signal_handling("libburner : ", NULL, 0);
burn_set_signal_handling("libburner : ", NULL, 0x0);
printf("Done\n");
return 1;
}
@ -401,7 +407,7 @@ int libburner_format(struct burn_drive *drive)
}
if (burn_is_aborting(0) > 0)
return -1;
burn_set_signal_handling("libburner : ", NULL, 0);
burn_set_signal_handling("libburner : ", NULL, 0x0);
burn_disc_get_profile(drive_list[0].drive, &current_profile,
current_profile_name);
if (current_profile == 0x14 || current_profile == 0x13)
@ -757,7 +763,7 @@ int main(int argc, char **argv)
/* Activate the synchronous signal handler which eventually will try to
properly shutdown drive and library on aborting events. */
burn_set_signal_handling("libburner : ", NULL, 0);
burn_set_signal_handling("libburner : ", NULL, 0x0);
/** Note: driveno might change its value in this call */
ret = libburner_aquire_drive(drive_adr, &driveno);