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[/] [openrisc/] [tags/] [gnu-src/] [newlib-1.18.0/] [newlib-1.18.0-or32-1.0rc1/] [newlib/] [libc/] [stdlib/] [envlock.c] - Rev 345
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/* FUNCTION <<__env_lock>>, <<__env_unlock>>---lock environ variable INDEX __env_lock INDEX __env_unlock ANSI_SYNOPSIS #include <envlock.h> void __env_lock (struct _reent *<[reent]>); void __env_unlock (struct _reent *<[reent]>); TRAD_SYNOPSIS void __env_lock(<[reent]>) struct _reent *<[reent]>; void __env_unlock(<[reent]>) struct _reent *<[reent]>; DESCRIPTION The <<setenv>> family of routines call these functions when they need to modify the environ variable. The version of these routines supplied in the library use the lock API defined in sys/lock.h. If multiple threads of execution can call <<setenv>>, or if <<setenv>> can be called reentrantly, then you need to define your own versions of these functions in order to safely lock the memory pool during a call. If you do not, the memory pool may become corrupted. A call to <<setenv>> may call <<__env_lock>> recursively; that is, the sequence of calls may go <<__env_lock>>, <<__env_lock>>, <<__env_unlock>>, <<__env_unlock>>. Any implementation of these routines must be careful to avoid causing a thread to wait for a lock that it already holds. */ #include "envlock.h" #include <sys/lock.h> #ifndef __SINGLE_THREAD__ __LOCK_INIT_RECURSIVE(static, __env_lock_object); #endif void __env_lock (ptr) struct _reent *ptr; { #ifndef __SINGLE_THREAD__ __lock_acquire_recursive (__env_lock_object); #endif } void __env_unlock (ptr) struct _reent *ptr; { #ifndef __SINGLE_THREAD__ __lock_release_recursive (__env_lock_object); #endif }