Topic       : The ATARI Compendium
Author      : Scott Sanders / JAY Software
Version     : 1.25 (20/6/2003)
Subject     : Documentation
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Compiled on : Atari
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View Ref-FilePsigreturn()
Psigblock()
Pkill()
Psignal()                                                            GEMDOS

Syntax

LONG Psignal( sig, handler )
WORD sig;
VOID (*handler)( LONG );

Function      Psignal() determines the action taken when a signal is
              received by the process.

Opcode        274 (0x112)

Availability  This function is available under all MiNT versions
              integrated with MultiTOS.

Parameters    sig specifies the signal whose response you wish to modify.
              If handler is cast to SIG_DFL (0) then the default action
              for the signal will occur when received. If handler is cast
              to SIG_IGN (1) then the signal will be ignored by the
              process. Otherwise, handler points to a user function which
              is designed to take action on a signal. This function is
              called when a signal is received with a LONG signal number
              on the stack.

Binding       pea      handler
              move.w   sig,-(sp)
              move.w   #$112,-(sp)
              trap     #1
              addq.l   #8,sp

Return Value  Psignal() returns the old value of the signal handler if
              successful or a negative GEMDOS error code otherwise.

Comments      Signal handler functions may make any GEMDOS, BIOS, or XBIOS
              calls desired but must not make any AES or VDI calls. Signal
              handlers must either return with a 680x0 RTS instruction to
              resume program execution or call Psigreturn() to clean the
              stack if it intends to do a 'C' longjmp(). Signal handling is
              preserved across Pfork() and Pvfork() calls. Child processes
              started with Pexec() ignore and follow the default action
              the same as their parents. Signals which have user functions
              assigned to them are reset to the default action for child
              processes.

See Also      Psigreturn(), Psigblock(), Pkill()