getpgidpidt

getpgidpidt is a name used in some software projects for a utility function that retrieves multiple identifiers associated with a process in a single call. In typical designs, it returns a small structure containing the process ID (PID), the process group ID (PGID), and the thread ID (TID) of a target process, usually the calling process when no pid is specified. The name is not part of the standard C library, and there is no universal standard for its interface; implementations vary between projects.

A common design pattern for getpgidpidt is to define a simple data structure to hold the identifiers and a function that fills this structure. For example, a structure might include fields for pid, pgid, and tid, and the function would take an optional pid parameter and a pointer to the structure to populate. A typical usage would resemble: define a type with fields pid, pgid, and tid, declare an instance, and call getpgidpidt with the desired pid and the address of the instance. On success, the fields hold the requested identifiers; on failure, the function returns an error code and sets an error indicator.

Platform considerations are important. getpid and getpgid are standard on POSIX systems, but obtaining a thread ID (TID) is Linux-specific and may require a direct system call or a platform-specific wrapper such as gettid. Because process group semantics and thread identification differ across operating systems, getpgidpidt is typically implemented with portability constraints or specialized in-kernel and user-space support.

Usage notes: such a function is most useful when code that needs to report or verify all three identifiers in one call, or when a single wrapper improves consistency across modules. See also getpid, getpgid, and gettid (or their equivalents on the target platform).