Updates that allow accum SWMR tests to work on Windows (#493)

* Committing clang-format changes

* Updates the accum test to work on Windows

Uses CreateProcess() on Windows

* Source formatting

* Fix for Unix child result

* Fixes process return code bug on Windows

Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>

Author: derobins

test/accum.c

@@ -2074,13 +2074,14 @@ HDfprintf(stderr, "Random # seed was: %u\n", seed);
 /*-------------------------------------------------------------------------
  * Function:    test_swmr_write_big
  *
- * Purpose:    	A SWMR test: verifies that writing "large" metadata to a file
- *		opened with SWMR_WRITE will flush the existing metadata in the
- *		accumulator to disk first before writing the "large" metadata
- *	 	to disk.
- *		This test will fork and exec a reader "accum_swmr_reader" which
- *		opens the same file with SWMR_READ and verifies that the correct
- *		metadata is read from disk.
+ * Purpose:     A SWMR test: verifies that writing "large" metadata to a file
+ *              opened with SWMR_WRITE will flush the existing metadata in the
+ *              accumulator to disk first before writing the "large" metadata
+ *              to disk.
+ *
+ *              This test will fork and exec a reader "accum_swmr_reader" which
+ *              opens the same file with SWMR_READ and verifies that the correct
+ *              metadata is read from disk.
  *
  * Return:      Success: 0
  *              Failure: 1
@@ -2092,24 +2093,31 @@ HDfprintf(stderr, "Random # seed was: %u\n", seed);
 unsigned
 test_swmr_write_big(hbool_t newest_format)
 {
-#ifdef H5_HAVE_UNISTD_H
+
     hid_t    fid  = -1;   /* File ID */
     hid_t    fapl = -1;   /* File access property list */
     H5F_t *  rf   = NULL; /* File pointer */
     char     filename[1024];
     uint8_t *wbuf2 = NULL, *rbuf = NULL; /* Buffers for reading & writing */
     uint8_t  wbuf[1024];                 /* Buffer for reading & writing */
     unsigned u;                          /* Local index variable */
-    pid_t    pid;                        /* Process ID */
-    int      status;                     /* Status returned from child process */
-    char *   driver         = NULL;      /* VFD string (from env variable) */
-    hbool_t  api_ctx_pushed = FALSE;     /* Whether API context pushed */
+    hbool_t  process_success = FALSE;
+    char *   driver          = NULL;  /* VFD string (from env variable) */
+    hbool_t  api_ctx_pushed  = FALSE; /* Whether API context pushed */
 
     if (newest_format)
         TESTING("SWMR write of large metadata: with latest format")
     else
         TESTING("SWMR write of large metadata: with non-latest-format")
 
+#if !defined(H5_HAVE_UNISTD_H) && !defined(H5_HAVE_WIN32_API)
+
+    /* Not a Windows or POSIX system */
+    SKIPPED();
+    HDputs("    Test skipped: Not a Windows or POSIX system.");
+    return 0;
+
+#else
     /* Skip this test if SWMR I/O is not supported for the VFD specified
      * by the environment variable.
      */
@@ -2219,56 +2227,94 @@ test_swmr_write_big(hbool_t newest_format)
     if (HDmemcmp(wbuf2, rbuf, (size_t)BIG_BUF_SIZE) != 0)
         TEST_ERROR;
 
-    /* Fork child process to verify that the data at [1024, 2014] does get written to disk */
-    if ((pid = HDfork()) < 0) {
-        HDperror("fork");
-        FAIL_STACK_ERROR;
-    }
-    else if (0 == pid) { /* Child process */
-        /* By convention, argv[0] tells the name of program invoked.
-         *
-         * execv on NetBSD 8 will actually return EFAULT if there is a
-         * NULL at argv[0], so we follow the convention unconditionally.
-         */
-        char        swmr_reader[] = SWMR_READER;
-        char *const new_argv[]    = {swmr_reader, NULL};
-        /* Run the reader */
-        status = HDexecv(SWMR_READER, new_argv);
-        HDprintf("errno from execv = %s\n", HDstrerror(errno));
-        FAIL_STACK_ERROR;
-    } /* end if */
+#if defined(H5_HAVE_WIN32_API)
+    {
+        STARTUPINFO         si;
+        PROCESS_INFORMATION pi;
+        DWORD               exit_code = EXIT_FAILURE;
 
-    /* Parent process -- wait for the child process to complete */
-    while (pid != HDwaitpid(pid, &status, 0))
-        /*void*/;
+        ZeroMemory(&si, sizeof(si));
+        si.cb = sizeof(si);
+        ZeroMemory(&pi, sizeof(pi));
 
-    /* Check if child process terminates normally and its return value */
-    if (WIFEXITED(status) && !WEXITSTATUS(status)) {
-        /* Flush the accumulator */
-        if (accum_reset(rf) < 0)
+        if (0 == CreateProcess(NULL, SWMR_READER, NULL, NULL, FALSE, 0, NULL, NULL, &si, &pi)) {
+            HDprintf("CreateProcess failed (%d).\n", GetLastError());
             FAIL_STACK_ERROR;
+        }
 
-        /* Close and remove the file */
-        if (H5Fclose(fid) < 0)
-            FAIL_STACK_ERROR;
+        (void)WaitForSingleObject(pi.hProcess, INFINITE);
+
+        if (FALSE == GetExitCodeProcess(pi.hProcess, &exit_code) || EXIT_FAILURE == exit_code)
+            process_success = FALSE;
+        else
+            process_success = TRUE;
 
-        /* Close the property list */
-        if (H5Pclose(fapl) < 0)
+        CloseHandle(pi.hProcess);
+        CloseHandle(pi.hThread);
+    }
+#else  /* defined(H5_HAVE_WIN32_API) */
+    {
+        pid_t pid;    /* Process ID */
+        int   status; /* Status returned from child process */
+
+        /* Fork child process to verify that the data at [1024, 2014] does get written to disk */
+        if ((pid = HDfork()) < 0) {
+            HDperror("fork");
+            FAIL_STACK_ERROR;
+        }
+        else if (0 == pid) { /* Child process */
+            /* By convention, argv[0] tells the name of program invoked.
+             *
+             * execv on NetBSD 8 will actually return EFAULT if there is a
+             * NULL at argv[0], so we follow the convention unconditionally.
+             */
+            char        swmr_reader[] = SWMR_READER;
+            char *const new_argv[]    = {swmr_reader, NULL};
+            /* Run the reader */
+            status = HDexecv(SWMR_READER, new_argv);
+            HDprintf("errno from execv = %s\n", HDstrerror(errno));
             FAIL_STACK_ERROR;
+        } /* end if */
 
-        /* Pop API context */
-        if (api_ctx_pushed && H5CX_pop(FALSE) < 0)
-            FAIL_STACK_ERROR
-        api_ctx_pushed = FALSE;
-
-        /* Release memory */
-        if (wbuf2)
-            HDfree(wbuf2);
-        if (rbuf)
-            HDfree(rbuf);
-        PASSED();
-        return 0;
-    } /* end if */
+        /* Parent process -- wait for the child process to complete */
+        while (pid != HDwaitpid(pid, &status, 0))
+            /*void*/;
+
+        /* Check if child process terminates normally and its return value */
+        if (WIFEXITED(status) && !WEXITSTATUS(status))
+            process_success = TRUE;
+    }
+#endif /* defined(H5_HAVE_WIN32_API) */
+
+    /* Check if the process terminated correctly */
+    if (!process_success)
+        FAIL_PUTS_ERROR("child process exited abnormally")
+
+    /* Flush the accumulator */
+    if (accum_reset(rf) < 0)
+        FAIL_STACK_ERROR;
+
+    /* Close and remove the file */
+    if (H5Fclose(fid) < 0)
+        FAIL_STACK_ERROR;
+
+    /* Close the property list */
+    if (H5Pclose(fapl) < 0)
+        FAIL_STACK_ERROR;
+
+    /* Pop API context */
+    if (api_ctx_pushed && H5CX_pop(FALSE) < 0)
+        FAIL_STACK_ERROR
+    api_ctx_pushed = FALSE;
+
+    /* Release memory */
+    if (wbuf2)
+        HDfree(wbuf2);
+    if (rbuf)
+        HDfree(rbuf);
+
+    PASSED();
+    return 0;
 
 error:
     /* Closing and remove the file */
@@ -2287,11 +2333,7 @@ test_swmr_write_big(hbool_t newest_format)
 
     return 1;
 
-#else  /* H5_HAVE_UNISTD_H */
-    SKIPPED();
-    HDputs("    Test skipped due to fork, waitpid, or pid_t not defined.");
-    return 0;
-#endif /* H5_HAVE_UNISTD_H */
+#endif /* !defined(H5_HAVE_UNISTD_H) && !defined(H5_HAVE_WIN32_API) */
 
 } /* end test_swmr_write_big() */