Function sys_wait 

pub fn sys_wait(_pid: u64) -> SyscallResult<i32>

Wait for a child process to exit and collect its exit status.

Blocks the calling process until the specified child process has terminated. Once the child exits, its exit code is returned and the child’s zombie entry is removed from the process table (reaped).

If the child has already exited before this call, the exit code is returned immediately without blocking (zombie reaping). If the specified PID does not correspond to a child of the calling process, an error is returned.

Future implementations may support WNOHANG-style behavior by passing special PID values:

• pid > 0: Wait for the specific child with that PID.
• pid == 0: Wait for any child in the same process group (future).
• pid == u64::MAX: Wait for any child process (future).

Arguments

• pid - Process ID of the child to wait for. Must be a direct child of the calling process.

Returns

• Ok(exit_code) - The exit status code of the terminated child process. By convention, 0 indicates success and non-zero values indicate an error or signal termination.

Errors

• SyscallError::NotFound - No child process with the given pid exists, or the specified process is not a child of the caller.
• SyscallError::InvalidArgument - The pid value is invalid (e.g., 0 when process group waiting is not yet supported).
• SyscallError::InternalError - An unexpected kernel error occurred during the wait operation.

Examples

use veridian_kernel::pkg::sdk::syscall_api::{sys_exit, sys_fork, sys_wait};

let child_pid = sys_fork().expect("fork failed");
if child_pid == 0 {
    // Child process work
    sys_exit(42);
} else {
    // Parent waits for child and retrieves exit code
    let exit_code = sys_wait(child_pid).expect("wait failed");
    // exit_code == 42
}