Windows System Programming Third Edition [Electronic resources] نسخه متنی

Figure 6-3 shows the processing performed by Program 6-1.

Program 6-1. grepMP: Parallel Searching

/*   Chapter 6. grepMP. */
/*   Multiple process version of grep command. */
#include "EvryThng.h"
int _tmain (DWORD argc, LPTSTR argv [])
/* Create a separate process to search each file on the
command line. Each process is given a temporary file,
in the current directory, to receive the results. */
{
HANDLE hTempFile;
SECURITY_ATTRIBUTES StdOutSA = /* SA for inheritable handle. */
{sizeof (SECURITY_ATTRIBUTES), NULL, TRUE};
TCHAR CommandLine [MAX_PATH + 100];
STARTUPINFO StartUpSearch, StartUp;
PROCESS_INFORMATION ProcessInfo;
DWORD iProc, ExCode;
HANDLE *hProc; /* Pointer to an array of proc handles. */
typedef struct {TCHAR TempFile [MAX_PATH];} PROCFILE;
PROCFILE *ProcFile; /* Pointer to array of temp file names. */
GetStartupInfo (&StartUpSearch);
GetStartupInfo (&StartUp);
ProcFile = malloc ((argc - 2) * sizeof (PROCFILE));
hProc = malloc ((argc - 2) * sizeof (HANDLE));
/* Create a separate "grep" process for each file. */
for (iProc = 0; iProc < argc - 2; iProc++) {
_stprintf (CommandLine, _T ("%s%s %s"),
_T ("grep "), argv [1], argv [iProc + 2]);
GetTempFileName (_T ("."), _T ("gtm"), 0,
ProcFile [iProc].TempFile); /* For search results. */
hTempFile = /* This handle is inheritable */
CreateFile (ProcFile [iProc].TempFile,
GENERIC_WRITE,
FILE_SHARE_READ | FILE_SHARE_WRITE, &StdOutSA,
CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
StartUpSearch.dwFlags = STARTF_USESTDHANDLES;
StartUpSearch.hStdOutput = hTempFile;
StartUpSearch.hStdError = hTempFile;
StartUpSearch.hStdInput = GetStdHandle (STD_INPUT_HANDLE);
/* Create a process to execute the command line. */
CreateProcess (NULL, CommandLine, NULL, NULL,
TRUE, 0, NULL, NULL, &StartUpSearch, &ProcessInfo);
/* Close unwanted handles. */
CloseHandle (hTempFile); CloseHandle (ProcessInfo.hThread);
hProc [iProc] = ProcessInfo.hProcess;
}
/* Processes are all running. Wait for them to complete. */
for (iProc = 0; iProc < argc - 2; iProc += MAXIMUM_WAIT_OBJECTS)
WaitForMultipleObjects ( /* Allows a large # of processes */
min (MAXIMUM_WAIT_OBJECTS, argc - 2 - iProc),
&hProc [iProc], TRUE, INFINITE);
/* Result files sent to std output using "cat." */
for (iProc = 0; iProc < argc - 2; iProc++) {
if (GetExitCodeProcess(hProc [iProc], &ExCode) && ExCode==0) {
/* Pattern was detected -- List results. */
if (argc > 3) _tprintf (_T ("%s:\n"), argv [iProc + 2]);
fflush (stdout); /* Multiple processes use stdout. */
_stprintf (CommandLine, _T ("%s%s"),
_T ("cat "), ProcFile [iProc].TempFile);
CreateProcess (NULL, CommandLine, NULL, NULL,
TRUE, 0, NULL, NULL, &StartUp, &ProcessInfo);
WaitForSingleObject (ProcessInfo.hProcess, INFINITE);
CloseHandle (ProcessInfo.hProcess);
CloseHandle (ProcessInfo.hThread);
}
CloseHandle (hProc [iProc]);
DeleteFile (ProcFile [iProc].TempFile);
}
free (ProcFile);
free (hProc);
return 0;
}