90 lines
2.5 KiB
Groff
90 lines
2.5 KiB
Groff
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. \" Manual Seite fuer handle
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. \" @(#)handle.3 1.1
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. \"
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.if t .ds a \v'-0.55m'\h'0.00n'\z.\h'0.40n'\z.\v'0.55m'\h'-0.40n'a
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.if t .ds s \(*b
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.if n .ds a ae
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.TH HANDLE 3 "15. Juli 1988" "J\*org Schilling" "Schily\'s LIBRARY FUNCTIONS"
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.SH NAME
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handle() \- sets a function to handle a condition
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.SH SYNOPSIS
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.nf
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.B
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#include <sigblk.h>
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.B
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handle(signame, sp, func, arg1)
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.B char *signame;
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.B SIGBLK *sp;
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.B int (*func)();
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.B long arg1;
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.fi
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.SH DESCRIPTION
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handle() sets up a handler for a condition. The user must
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explicitly allocate the condition block and pass it to the
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function.
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.PP
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handle() establishes function func as the condition handler for
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the condition signame. arg1 is passed to func at the time of
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condition signalling. signame "any_other", catches all
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conditions.
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.PP
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The specified function is called with the actual condition being
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signalled, with arguments from the latest handle() call for that
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function in the given frame and from the call to raise(). For
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instance:
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.PP
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.nf
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.B
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int func (signame, arg1, arg2)
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.B
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char *signame; /* the actual condition being
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.B
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/* signalled */
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.B
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int arg1; /* arg1 comes from the handle
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.B
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/* call that set up the handler */
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.B
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int arg2; /* arg2 comes from the raise call */
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.fi
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.PP
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If the function returns TRUE (non-zero), it is assumed that the
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condition has been successfully handled; otherwise, the
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condition is signalled farther down the stack.
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.SH RETURNS
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none
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.SH NOTES
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Be careful when declaring args to func if they are not long;
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both args will occupy sizeof(long) bytes in the arglist.
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If FALSE is returned by a condition handler, and there is an
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any_other handler in the same block, the any_other handler will
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be invoked (only once, since it too may return FALSE).
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.PP
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To revert a condition handler simply use NULL as func.
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.PP
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SIGBLK, defined in <sigblk.h>, must be included.
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handle() is frequently used with longjmp() and setjmp().
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.PP
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Eah function which calls
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.I handle()
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must call
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.I unhandle()
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before it returns. Otherwise the return will fail.
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.SH BUGS
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.I Handle()
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makes the framepointer odd, to mark the current stack frame.
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.PP
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This confuses programs like
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.B adb(1)
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and
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.B dbx(1).
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