Somewhere between 4.1.1 and 4.2.3, the return value from pclose changed.
The exit status used to be in the second byte, so that the status would be (pclose($fp)/256).
It is now in the low-order byte, so the status is just pclose($fp).
Be careful.
pclose
说明
int pclose ( resource handle )关闭用 popen() 打开的指向管道的文件指针。
文件指针必须有效，且必须是成功调用 popen() 所返回的。
返回运行的进程的终止状态。
参见 popen()。
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User Contributed Notes
kcross at nssolutions dot com
17-Jul-2003 05:08
17-Jul-2003 05:08
vdweij at mailsurf dot com
12-Mar-2003 11:18
12-Mar-2003 11:18
As I understand pclose will return 0 (on every platform) in case popen could not execute the specified command.
Since popen only returns the status wether it was able to send a command and not wether it was succesfully executed. Only the returned value of pclose can be used to check wether a command could be executed.
roel at bouwman dot net
08-Oct-1999 01:23
08-Oct-1999 01:23
The return value of pclose() is not the exit status of the program, but a value as returned by waitpid() of wait4().
To obtain the exit status:
$ret=(pclose($f)>>8)&0xFF;