system command's output

This is a discussion on system command's output within the C Programming forums, part of the General Programming Boards category; i want to save a system command's output in a file without displaying it on screen. i thought of defining ...

  1. #1
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    system command's output

    i want to save a system command's output in a file without displaying it on screen. i thought of defining stdout to the file i want and haven't tested it yet. Any other ideas?

  2. #2
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    thanx

  3. #3
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    I have written this. It compiles fine, when i run it
    the info file is created and hello world is written in the
    file but then i get the "this program has performed an illegal
    operation" error.
    Error while opening file is not printed.

    Code:
    #include <stdio.h>
    #include <stdlib.h>
    
    void copyFile (FILE * input, FILE * output)
    {
        int c;
        while ( (c=getc(input)) != EOF)
            putc(c,output);
    }
    
    
    int main ()
    {
        FILE * pr;
        system("hello > c:\\info"); //hello just prints hello world
        if ((pr = fopen("r","c:\\info")) == NULL)
    	fprintf(stderr, "Error while opening info file");
        copyFile(pr, stdout);
        return 0;
    }

  4. #4
    End Of Line Hammer's Avatar
    Join Date
    Apr 2002
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    6,231
    Also, checkout the (non-standard) popen() or _popen() function if you have it. It might be of some use to you, depending on what you're trying to accomplish.
    When all else fails, read the instructions.
    If you're posting code, use code tags: [code] /* insert code here */ [/code]

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