From owner-freebsd-questions  Sat Jun 26  7:17: 5 1999
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Date: Sat, 26 Jun 1999 22:17:22 +0800
From: Peihan Wang <peihanw@mx.cei.gov.cn>
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Subject: char* getenv(const char*) (3)
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I am writing a simple program which calling 
lib function getenv().

But there is something I can not explain.
The code
    char * cp = getenv("PATH");
works fine,
while other two usage
    cp = getenv("PPID");
    cp = getenv("PIPESTATUS");
just return NULL.

Under shell(bash2.01), I type
$ set
...
PATH=/sbin:/usr/sbin:/bin:/usr/bin....
PIPESTATUS=([0]="0")
PPID=258
...
$ echo $PPID
258
$ echo $PIPESTATUS
0

Why getenv does not work with PPID & PIPESTATUS ?
How shell obtain these info ?

Thanx.


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