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mirror of git://sourceware.org/git/newlib-cygwin.git synced 2025-01-16 03:19:54 +08:00
Jeff Johnston d0bd3e6f56 2004-06-11 Antony King <antony.king@st.com>
* libc/include/sys/_types.h: Include <sys/lock.h> and change
        _flock_t to be of type _LOCK_RECURSIVE_T.
        * libc/include/sys/reent.h: (_REENT_INIT): Reformat.
        (_REENT_INIT_PTR): Ditto.  Use memset where appropriate.
        (_global_impure_ptr): New declaration.
        (_GLOBAL_REENT): Change to be _global_impure_ptr.
        * libc/include/sys/stdio.h: Include <sys/lock.h> and
        <sys/reent.h>.
        (_flockfile)[!_SINGLE_THREAD]: Add code for lock call.
        (_funlockfile)[!SINGLE_THREAD]: Ditto.
        * libc/reent/impure.c: Set _global_impure_ptr to _impure_ptr.
        * libc/stdio/fclose.c: Remove casting of fp lock to
        _LOCK_RECURSIVE_T.
        * libc/stdio/findfp.c: Ditto.
        * libc/stdio/fopen.c: Ditto.
        * libc/stdio/freopen.c: Ditto.
        * libc/stdio/vfprintf.c: Ditto.
        * libc/stdio64/fopen64.c: Ditto.
        * libc/stdlib/envlock.c: Add default stubs that use generic
        locking code.
        * libc/stdlib/mlock.c: Ditto.

        Jeff Johnston  <jjohnstn@redhat.com>
        * libc/sys/linux/sys/_types.h (__flock_mutex_t): New subtype.
        (_flock_t): Change to be a struct containing a single member
        named mutex which is of type __flock_mutex_t.
2004-06-11 20:37:10 +00:00

62 lines
1.5 KiB
C

/*
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
}