41 lines
1.3 KiB
Scheme
41 lines
1.3 KiB
Scheme
;;; Scsh routines for analysing exit codes returned by WAIT.
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;;; Copyright (c) 1994 by Olin Shivers. See file COPYING.
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;;;
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;;; To port these to a new OS, consult /usr/include/sys/wait.h,
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;;; and check the WIFEXITED, WEXITSTATUS, WIFSTOPPED, WSTOPSIG,
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;;; WIFSIGNALED, and WTERMSIG macros for the magic fields they use.
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;;; These definitions are for Linux.
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;;;
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;;; I could have done a portable version by making C calls for this,
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;;; but it's such overkill.
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;;; If process terminated normally, return the exit code, otw #f.
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(define (status:exit-val status)
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(and (not (= (bitwise-and #xFF status) #x7F))
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(zero? (bitwise-and #x7F status))
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(bitwise-and #xFF (arithmetic-shift status -8))))
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;;; If the process was suspended, return the suspending signal, otw #f.
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(define (status:stop-sig status)
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(and (= #x7F (bitwise-and status #xFF))
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(bitwise-and #xFF (arithmetic-shift status -8))))
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;;; If the process terminated abnormally,
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;;; return the terminating signal, otw #f.
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(define (status:term-sig status)
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(let ((termsig (bitwise-and status #x7F)))
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(and (not (zero? termsig)) ; Didn't exit.
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(not (= #x7F (bitwise-and status #xFF))) ; Not suspended.
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termsig)))
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;;; Flags.
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(define wait/poll 1) ; Don't hang if nothing to wait for.
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(define wait/stopped-children 2) ; Report on suspended subprocs, too.
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