while debugging using GDB No output after calling a user defined function in C

Question

While debugging using gdb, I am calling the nc_print function as
(gdb)call nc_print() but there is no output and no warning.

void nc_print()
{
     printf("ramanuj\n");
}

I am finding that gdb fails to call the nc_print. I am not getting why is it happening. May i know the possible reason.

I can't reproduce it, can you post whole gdb session from very beginning ? — ks1322
– ks1322, Commented Nov 23, 2016 at 16:48
atleast you can say in which situation gdb fails to call the function — user2468460
– user2468460, Commented Nov 23, 2016 at 23:24

Employed Russian · Accepted Answer · 2016-11-24 00:36:55Z

2

I am finding that gdb fails to call the nc_print.

Your conclusion that GDB did not call nc_print is likely wrong. If you add a call to abort() to nc_print, does your program abort? If so, your conclusion is wrong.

I am not getting why is it happening

What is most likely happening is that your inferior (being debugged) program has its stdout redirected to a file (or a pipe), and thus fully buffered.

Things will likely work as you expect them if you add fflush(stdout), or use fprintf(stderr, "ramanuj\n").

answered Nov 24, 2016 at 0:36

Employed Russian

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user2468460 Over a year ago

Many Thanks It works. Is there any way to increase the buffer size while debugging.

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