49 lines
1.2 KiB
C
49 lines
1.2 KiB
C
/*
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FUNCTION
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<<__env_lock>>, <<__env_unlock>>--lock environ variable
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INDEX
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__env_lock
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INDEX
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__env_unlock
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ANSI_SYNOPSIS
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#include "envlock.h"
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void __env_lock (void *<[reent]>);
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void __env_unlock (void *<[reent]>);
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TRAD_SYNOPSIS
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void __env_lock(<[reent]>)
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char *<[reent]>;
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void __env_unlock(<[reent]>)
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char *<[reent]>;
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DESCRIPTION
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The <<setenv>> family of routines call these functions when they need
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to modify the environ variable. The version of these routines supplied
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in the library does not do anything. If multiple threads of execution
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can call <<setenv>>, or if <<setenv>> can be called reentrantly, then
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you need to define your own versions of these functions in order to
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safely lock the memory pool during a call. If you do not, the memory
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pool may become corrupted.
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A call to <<setenv>> may call <<__env_lock>> recursively; that is,
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the sequence of calls may go <<__env_lock>>, <<__env_lock>>,
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<<__env_unlock>>, <<__env_unlock>>. Any implementation of these
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routines must be careful to avoid causing a thread to wait for a lock
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that it already holds.
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*/
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void
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__env_lock (ptr)
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struct _reent *ptr;
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{
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}
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void
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__env_unlock (ptr)
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struct _reent *ptr;
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{
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}
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