get command output in pipe, C for Linux

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一向
一向 2020-12-04 00:19

I need to run a Linux CLI command and get its stdout output from C.

I can use pipe() to create a pipe, then fork/exec, redirecting child\'s stdout descriptor into th

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  •  南笙
    南笙 (楼主)
    2020-12-04 00:53

    Is this it?

    NAME
           popen, pclose - process I/O
    
    SYNOPSIS
           #include   
    
           FILE *popen(const char *command, const char *type);
    
           int pclose(FILE *stream);
    
    DESCRIPTION
           The  popen()  function opens a process by creating a pipe, forking, 
    and invoking the shell.  Since a pipe is by definition unidirectional, the 
    type argument may specify only reading or writing, not both; the resulting 
    stream is correspondingly read-only or write-only.
    
           The command argument is a pointer to a null-terminated string 
    containing a shell command line.  This command is passed to /bin/sh 
    using the -c flag; interpretation, if any, is performed by the shell.  
    The type argument is a pointer to a null-terminated string which must be 
    either ‘r’ for reading or ‘w’ for writing.
    
           The  return  value  from popen() is a normal standard I/O stream in 
    all respects save that it must be closed with pclose() rather than fclose().  
    Writing to such a stream writes to the standard input of the command; the 
    command’s standard output is the same as that of the process that called 
    popen(), unless this is altered by the command itself.  Conversely, reading 
    from a ‘‘popened’’ stream reads the command’s standard output, and the 
    command’s standard input is the same as that of the process that called 
    popen().
    
           Note that output popen() streams are fully buffered by default.
    
           The pclose() function waits for the associated process to terminate 
    and returns the exit status of the command as returned by wait4().
    

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