Pull in some of the lpt_port_test fixes from lpt.c.

[unix-history] / lib / libpthread / pthreads / file.c

diff --git a/lib/libpthread/pthreads/file.c b/lib/libpthread/pthreads/file.c
index abca47b..d2cafc6 100644 (file)
--- a/lib/libpthread/pthreads/file.c
+++ b/lib/libpthread/pthreads/file.c
@@ -1,5 +1,5 @@
 /* ==== file.c ============================================================
 /* ==== file.c ============================================================

- * Copyright (c) 1993 by Chris Provenzano, proven@mit.edu
+ * Copyright (c) 1993, 1994 by Chris Provenzano, proven@mit.edu

  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without


@@ -29,14 +29,14 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
  * SUCH DAMAGE.
  *
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
  * SUCH DAMAGE.
  *

- * Description : All the new stdio functions.
+ * Description : The locking functions for stdio.

  *
  *  1.00 93/09/04 proven
  *      -Started coding this file.
  */
 
  *
  *  1.00 93/09/04 proven
  *      -Started coding this file.
  */
 

-#include "pthread.h"
-#include <stdio.h> /* Remove this when the stdio library is done. */
+#include <pthread.h>
+#include <stdio.h>

 
 /* ==========================================================================
  * flockfile()
 
 /* ==========================================================================
  * flockfile()


@@ -53,12 +53,42 @@ void flockfile(FILE *fp)
        }
 
        if (fd_table[fd]->r_owner != pthread_run) {
        }
 
        if (fd_table[fd]->r_owner != pthread_run) {

+               /* This might fail but POSIX doesn't give a damn. */

                fd_basic_lock(fd, FD_RDWR, lock);
        }
        fd_table[fd]->lockcount++;
        SEMAPHORE_RESET(lock);
 }
 
                fd_basic_lock(fd, FD_RDWR, lock);
        }
        fd_table[fd]->lockcount++;
        SEMAPHORE_RESET(lock);
 }
 

+/* ==========================================================================
+ * ftrylockfile()
+ */
+int ftrylockfile(FILE *fp)
+{
+       semaphore *lock;
+       int fd;
+
+       fd = fileno(fp);
+       lock = &(fd_table[fd]->lock);
+       while (SEMAPHORE_TEST_AND_SET(lock)) {
+               pthread_yield();
+       }
+
+       if (fd_table[fd]->r_owner != pthread_run) {
+               if (!(fd_table[fd]->r_owner && fd_table[fd]->w_owner)) {
+                       fd_basic_lock(fd, FD_RDWR, lock);
+                       fd = OK;
+               } else {
+                       fd = NOTOK;
+               }
+       } else {
+               fd_table[fd]->lockcount++;
+               fd = OK;
+       }
+       SEMAPHORE_RESET(lock);
+       return(fd);
+}
+

 /* ==========================================================================
  * funlockfile()
  */
 /* ==========================================================================
  * funlockfile()
  */