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POfopen() stream to popen() for progress bar/controll - but how to get stdout of popen()?
 

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  1. POfopen() stream to popen() for progress bar/controll - but how to get stdout of popen()?
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    <p>I'm trying to write simple c function which would give me possibility to see progress of data transfer from one stream to other stream and display it on my char LCD.</p> <p>I manage to transfer the data and indicate the progress but how to get result of the piping?</p> <p>So basically i want to do in c corresponds to shell command:</p> <pre><code>/home/image.img | md5sum &gt; result </code></pre> <p>The problem i have i with the stdout. I would like to get it to a char * result.</p> <p>In other words the md5sum returns a string on the screen like this "5193fd9ebfa30bcb914e7af4760deb15" but i would like to get it to my char * result for further usage in the function.</p> <pre><code>FILE *in_stream, *out_stream; #define TRANSFER_BLOCK_SIZE 1048576 //one MB int n=0; int i=0; long int input_size=0; unsigned char buffer[TRANSFER_BLOCK_SIZE]; if((out_stream=popen("md5sum","w"))==NULL) { perror(output_pipe_name); return 1; } if((in_stream=fopen("/home/gregorek/image.img","r"))==NULL) { perror(input_file_name); return 1; } //check total size of the input file fseek(in_stream,0,SEEK_END); input_size=(ftell(in_stream)/TRANSFER_BLOCK_SIZE)+1; fseek(in_stream,0,SEEK_SET); // do { i++; memset(buffer,'\0',TRANSFER_BLOCK_SIZE); n=fread(buffer,sizeof(unsigned char),TRANSFER_BLOCK_SIZE,in_stream); lcd_display(i); //this is my progress indicator fwrite(buffer,sizeof(unsigned char),n,out_stream); } while(!feof(in_stream)); fclose(in_stream); pclose(out_stream); </code></pre> <p>return 0;<br> }</p> <p>thanks</p>
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    1. USGregorek
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    1. COWhat kind of command is this `/home/image.img | md5sum > result`? `image.img` is an executable?
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      1. POfopen() stream to popen() for progress bar/controll - but how to get stdout of popen()?
      1. USalk
 

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