v0.40: Create exercises. Challenge the community.

pipe_chain

Your mission

Implement pipe_chain, a compact pipeline executor for already-tokenized commands.

See it in action

pipe_chain({{"printf", "alpha\\nbeta\\n", NULL}, {"grep", "beta", NULL}, NULL})

Expected result

beta\n

Your checklist

For your own tracking. Tests grade your code.

Create pipe_chain.c.
Expose int pipe_chain(char **cmds[]);.
cmds is a NULL-terminated array of commands.
Each command is an argv-style NULL-terminated array ready to pass to execvp.
Run every command in order and connect command N standard output to command N+1 standard input.
Wait for every child process before returning.
Return 0 when the pipeline was launched and waited successfully.
Return 1 if a system call needed by the pipeline fails.
Close all pipe file descriptors in parent and child processes as soon as they are no longer needed.

Constraints

Expected files

pipe_chain.c

Allowed functions

closeforkwaitexitexecvpdup2pipe

Allowed headers

<unistd.h>declares close, fork, execvp, dup2 and pipe

<sys/wait.h>declares wait

<stdlib.h>declares exit

<stddef.h>defines NULL

pipe_chain

Processes and signals

Your mission

Implement pipe_chain, a compact pipeline executor for already-tokenized commands.

See it in action

pipe_chain({{"printf", "alpha\\nbeta\\n", NULL}, {"grep", "beta", NULL}, NULL})

Expected result

beta\n

Your checklist

For your own tracking. Tests grade your code.

Create pipe_chain.c.
Expose int pipe_chain(char **cmds[]);.
cmds is a NULL-terminated array of commands.
Each command is an argv-style NULL-terminated array ready to pass to execvp.
Run every command in order and connect command N standard output to command N+1 standard input.
Wait for every child process before returning.
Return 0 when the pipeline was launched and waited successfully.
Return 1 if a system call needed by the pipeline fails.
Close all pipe file descriptors in parent and child processes as soon as they are no longer needed.

Constraints

Expected files

pipe_chain.c

Allowed functions

closeforkwaitexitexecvpdup2pipe

Allowed headers

<unistd.h>declares close, fork, execvp, dup2 and pipe

<sys/wait.h>declares wait

<stdlib.h>declares exit

<stddef.h>defines NULL

Tests

Run the tests to grade your code

Build your code, then check each test here. Open a result to inspect its output.

Build

01Single command still runsWaiting

02Two-command pipeline filters stdoutWaiting

03Three-command pipeline preserves transformed outputWaiting

04A command may produce no outputWaiting

05Four commands close and pass every pipe correctlyWaiting

pipe_chain

Your mission

Implement pipe_chain, a compact pipeline executor for already-tokenized commands.

See it in action

pipe_chain({{"printf", "alpha\\nbeta\\n", NULL}, {"grep", "beta", NULL}, NULL})

Expected result

beta\n

Your checklist

For your own tracking. Tests grade your code.

Create pipe_chain.c.
Expose int pipe_chain(char **cmds[]);.
cmds is a NULL-terminated array of commands.
Each command is an argv-style NULL-terminated array ready to pass to execvp.
Run every command in order and connect command N standard output to command N+1 standard input.
Wait for every child process before returning.
Return 0 when the pipeline was launched and waited successfully.
Return 1 if a system call needed by the pipeline fails.
Close all pipe file descriptors in parent and child processes as soon as they are no longer needed.

Constraints

Expected files

pipe_chain.c

Allowed functions

closeforkwaitexitexecvpdup2pipe

Allowed headers

<unistd.h>declares close, fork, execvp, dup2 and pipe

<sys/wait.h>declares wait

<stdlib.h>declares exit

<stddef.h>defines NULL

v0.40: Create exercises. Challenge the community.

Meet Studio →

pipe_chain

Processes and signals

Your mission

Implement pipe_chain, a compact pipeline executor for already-tokenized commands.

See it in action

pipe_chain({{"printf", "alpha\\nbeta\\n", NULL}, {"grep", "beta", NULL}, NULL})

Expected result

beta\n

Your checklist

For your own tracking. Tests grade your code.

Create pipe_chain.c.
Expose int pipe_chain(char **cmds[]);.
cmds is a NULL-terminated array of commands.
Each command is an argv-style NULL-terminated array ready to pass to execvp.
Run every command in order and connect command N standard output to command N+1 standard input.
Wait for every child process before returning.
Return 0 when the pipeline was launched and waited successfully.
Return 1 if a system call needed by the pipeline fails.
Close all pipe file descriptors in parent and child processes as soon as they are no longer needed.

Constraints

Expected files

pipe_chain.c

Allowed functions

closeforkwaitexitexecvpdup2pipe

Allowed headers

<unistd.h>declares close, fork, execvp, dup2 and pipe

<sys/wait.h>declares wait

<stdlib.h>declares exit

<stddef.h>defines NULL

Tests

Run the tests to grade your code

Build your code, then check each test here. Open a result to inspect its output.

Build

01Single command still runsWaiting

02Two-command pipeline filters stdoutWaiting

03Three-command pipeline preserves transformed outputWaiting

04A command may produce no outputWaiting

05Four commands close and pass every pipe correctlyWaiting