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Macro problem

Discussion in 'C' started by techme, May 22, 2010.

  1. techme

    techme New Member

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    I had a situation in a C program, which contained hundreds of calls to
    "fprintf (stdout, ...", where I needed to flush stdout immediately
    after any stream was sent there. More specifically, I needed to add the
    command "fflush(stdout);" after every command that started with:

    fprintf(stdout
    fprintf (stdout
    fprintf( stdout
    fprintf ( stdout
    fprintf ( stdout
    etc.

    I wound up doing this manually (took about 30 minutes), but I later
    thought that I could have defined a macro to take care of this
    substitution. However, I couldn't even begin to think of the definition
    needed to handle every variable length fprintf call.

    Any ideas?

    Thanks.
     
  2. creative

    creative New Member

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    No Such Luck wrote:
    I had a situation in a C program, which contained hundreds of calls
    to
    "fprintf (stdout, ...", where I needed to flush stdout immediately
    after any stream was sent there. More specifically, I needed to add
    the
    command "fflush(stdout);" after every command that started with:

    fprintf(stdout

    Are you familiar with variadic macros?

    In C99 you could do something like

    #define print_it(file_ptr, format, ...) do \
    if (fprintf(file_ptr, format, ##__VA_ARGS__ ) == 0)
    fflush(file_ptr);
    /* else... handle the error if you like */
    while(0)
     
  3. techinspiration

    techinspiration New Member

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    Try it i have seen it.
     
  4. creative

    creative New Member

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    You can also try it;
     

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