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Top Forums Programming C++ How to use pipe() & fork() with stdin and stdout to another program Post 302178133 by vvaidyan on Monday 24th of March 2008 06:51:43 PM
Old 03-24-2008
C++ How to use pipe() & fork() with stdin and stdout to another program

Hi,
Program A: uses pipe()

I am able to read the stdout of PROGAM B (stdout got through system() command) into PROGRAM A using:

* child
-> dup2(fd[1], STDOUT_FILENO);
-> execl("/path/PROGRAM B", "PROGRAM B", NULL);

* parent
-> char line[100];
-> read(fd[0], line, 100);


Question:
---------
How to write to stdin of PROGRAM B from PROGRAM A?
* should I use a different pipe?
* how to I read stdin in PROGRAM B? using cin?

Thanks in advance,
Vivek

Last edited by vvaidyan; 04-30-2008 at 01:33 PM.. Reason: Question made more precise
 

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TAU_PROFILE_SET_NODE(3) 				      TAU Instrumentation API					   TAU_PROFILE_SET_NODE(3)

NAME
TAU_PROFILE_SET_NODE - Informs the measurement system of the node id SYNOPSIS
C/C++: TAU_PROFILE_SET_NODE(int node); Fortran: TAU_PROFILE_SET_NODE(integer node); DESCRIPTION
The TAU_PROFILE_SET_NODE macro sets the node identifier of the executing task for profiling and tracing. Tasks are identified using node, context and thread ids. The profile data files generated will accordingly be named profile.<node>.<context>.<thread>. Note that it is not necessary to call TAU_PROFILE_SET_NODE when using the TAU MPI wrapper library. EXAMPLE
C/C++ : int main (int argc, char **argv) { int ret, i; pthread_attr_t attr; pthread_t tid; TAU_PROFILE_TIMER(tautimer,"main()", "int (int, char **)", TAU_DEFAULT); TAU_PROFILE_START(tautimer); TAU_PROFILE_INIT(argc, argv); TAU_PROFILE_SET_NODE(0); /* ... */ TAU_PROFILE_STOP(tautimer); return 0; } Fortran : PROGRAM SUM_OF_CUBES integer profiler(2) / 0, 0 / save profiler INTEGER :: H, T, U call TAU_PROFILE_INIT() call TAU_PROFILE_TIMER(profiler, 'PROGRAM SUM_OF_CUBES') call TAU_PROFILE_START(profiler) call TAU_PROFILE_SET_NODE(0) ! This program prints all 3-digit numbers that ! equal the sum of the cubes of their digits. DO H = 1, 9 DO T = 0, 9 DO U = 0, 9 IF (100*H + 10*T + U == H**3 + T**3 + U**3) THEN PRINT "(3I1)", H, T, U ENDIF END DO END DO END DO call TAU_PROFILE_STOP(profiler) END PROGRAM SUM_OF_CUBES SEE ALSO
TAU_PROFILE_SET_CONTEXT(3) 08/31/2005 TAU_PROFILE_SET_NODE(3)
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