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@(#)fork.2 6.4 (Berkeley) 5/22/86
#include <sys/types.h> #include <unistd.h> pid_t fork(void)
The child process has a unique process ID.
The child process has a different parent process ID (i.e., the process ID of the parent process).
The child process has its own copy of the parent's descriptors. These descriptors reference the same underlying objects, so that, for instance, file pointers in file objects are shared between the child and the parent, so that an lseek (2) on a descriptor in the child process can affect a subsequent read or write by the parent. This descriptor copying is also used by the shell to establish standard input and output for newly created processes as well as to set up pipes.
The child starts with no pending signals and an inactive alarm timer.
15 [EAGAIN] The system-imposed limit on the total number of processes under execution would be exceeded. This limit is configuration-dependent. (The kernel variable NR_PROCS in <minix/config.h> (Minix), or <minix/const.h> (Minix-vmd).)
15 [ENOMEM] There is insufficient (virtual) memory for the new process.