_popen,_wpopen這是C執行庫(當然popen函式為Linux C)

CreatePipe function這是API函式

system函式可以執行命令列，並不能獲得顯示結果，執行結果則是通過管道來完成的。首先用popen開啟一個命令列的管道，然後通過fgets獲得該管道傳輸的內容，也就是命令列執行的結果

一、函式介紹

  1._popen

FILE *_popen(
    const char *command,
    const char *mode
);
FILE *wpopen(
    const wchar_t *command,
    const wchar_t *mode
);

mode:

"r"
The calling process can read the spawned command's stantard output using the returned stream

"w"
The calling process can write to the spawned command's standard input using the returned stream.

"b"
Open in binary mode.

"t"
Open in text mode.
 

   2._pclose

int _pclose(
    FILE *stream
);

     Generic-Text Routine Mappings

二、案例

  1._popen

#include "stdafx.h"
#include "stdlib.h"
int main() 
{
    FILE *fp;
    char buf[255] = {0};
    if ((fp = _popen("ipconfig", "r")) == NULL) {
        perror("Fail to popen\n");
        exit(1);
    }
    while (fgets(buf, 255, fp) != NULL) {
        printf("%s", buf);
    }

    _pclose(fp);
    return 0;
}
 

  2._wpopen

#include "stdafx.h"
#include "stdlib.h"
int main()
{
    FILE *fp;
    char buf[255] = {0};
    if ((fp = _wpopen(_T("ipconfig"), _T("r"))) == NULL) {
        perror("Fail to popen\n");
        exit(1);
    }
    while (fgets(buf, 255, fp) != NULL) {
        printf("%s", buf);
    }
    _pclose(fp);
    return 0;
}
 

 3.sample

//crt_popen.c
/* This program uses _popen and _pclose to receive a 
 * stream of text from a system process.
 */

#include <stdio.h>
#include <stdlib.h>

int main(void)
{
    char psBuffer[128];
    FILE *pPipe;

    /*Run DIR so that it writes its output to a pipe. Open this
    * pipe with read text attribute so that we can read it 
    * like a text file.
    */
    if ((pPipe = _popen("dir *.c /on /p", "rt")) == NULL) 
        exit(1);

    /*Read pipe until end of file, or an error occurs. */
    while (fgets(psBuffer, 128, pPipe)) {
        printf(psBuffer);
    }

    /*Close pipe and print return value of pPipe */
    if (feof(pPipe)) {
        printf("\nProcess returned %d\n", _pclose(pPipe));
    } else {
        printf("Error: Failed to read the pipe to the end.\n");
    }
}

Sample Output



This output assumes that there is only one file in the current directory with a .c file name extension.
 
 
 Volume in drive C is CDRIVE  
 Volume Serial Number is 0E17-1702  
  
 Directory of D:\proj\console\test1  
  
07/17/98  07:26p                   780 popen.c  
               1 File(s)            780 bytes  
                             86,597,632 bytes free  
  
Process returned 0

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