posixspawnattrt

posix_spawnattr_t is a data type defined by POSIX that represents a collection of attributes used by the posix_spawn function when creating a new process. It provides a portable way to influence how a child process is initialized, separate from the program image that will be executed. The attributes controlled through this object cover aspects such as the child’s process group, scheduling parameters and policy, and signal handling behavior. Using posix_spawnattr_t, a program can tailor the child’s environment without forking first.

The posix_spawnattr_t object is opaque to the programmer and must be managed with a defined lifecycle. It is initialized with an initialization function and later destroyed with a corresponding destruction function when it is no longer needed. The current set of attributes is tracked via a flags field that indicates which attributes have been set. Access and modification of the attributes are performed through a family of getter and setter functions; typical capabilities include retrieving and setting the active flags, the child process group, scheduling parameters and policy, and various signal-related configurations. The exact attributes available can vary by platform and implementation.

In practice, programs use posix_spawnattr_t in conjunction with posix_spawn_file_actions_t and posix_spawn to create a new process in a single call. After initializing the attr object, a programmer may selectively enable and configure attributes, then invoke posix_spawn to start the new process with the specified attributes. If an attribute is not set, the child inherits the default behavior of the system. The POSIX standard defines these interfaces to improve portability across Unix-like systems, though exact support for individual attributes may differ between kernels and C libraries.