ns_fork(3aolserv) [debian man page]

Ns_Exec(3aolserver)					   AOLserver Library Procedures 				       Ns_Exec(3aolserver)

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NAME

       Ns_ExecArgblk,  Ns_ExecArgv,  Ns_ExecProc,  Ns_ExecProcess,  Ns_Fork,  Ns_GetEnviron, Ns_WaitForProcess, Ns_WaitProcess, ns_fork - External
       process execution

SYNOPSIS

       #include "ns.h"

       int
       Ns_ExecArgblk(char *exec, char *dir, int fdin, int fdout,
		     char *args, Ns_Set *env)

       int
       Ns_ExecArgv(char *exec, char *dir, int fdin, int fdout,
		   char **argv, Ns_Set *env)

       int
       Ns_ExecProc(char *exec, char **argv)

       int
       Ns_ExecProcess(char *exec, char *dir, int fdin, int fdout,
		      char *args, Ns_Set *env)

       int
       Ns_Fork(void)

       char
       **Ns_GetEnviron(void)

       int
       Ns_WaitForProcess(int pid, int *statusPtr)

       int
       Ns_WaitProcess(int pid)

       int
       ns_fork(void)
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DESCRIPTION

       These functions handle fork and exec operations. See files: nsd/exec.c, nsd/tclenv.c and nsthread/fork.c.

       Ns_ExecArgblk(exec, dir, fdin, fdout, args, env)

	      Executes a command in a child process. Return process id of child process exec'ing the command or -1 on failure.	Provides  extended
	      error checking and error messages.

       Ns_ExecArgv(exec, dir, fdin, fdout, argv, env)

	      Execute a command in a child process using fork(2) and execve(2), returns the process id of child process exec'ing the command or -1
	      on failure. The child sends an extended error message to the parent.

       Ns_ExecProc(exec, argv)

	      Executes a command in a child process. Returns the process id of the child process exec'ing the command or -1 on	failure.   Simpli-
	      fies call to Ns_ExecArgv.

       Ns_ExecProcess(exec, dir, fdin, fdout, args, env)

	      Executes	a  command  in	a child process. Returns the process id of the child process exec'ing the command or -1 on failure.  Calls
	      Ns_ExecArgblk with same arguments.

       Ns_Fork()
	      Posix style fork(), using fork1() on Solaris if needed. See fork(2) man page. Calls ns_fork.

       Ns_GetEnviron()

	      Returns pointer to the environment vector.

       Ns_WaitForProcess(pid, statusPtr)

	      Wait for child process. Returns NS_OK on success, or NS_ERROR on failure. *statusPtr is set to the exit code of the child process.

       Ns_WaitProcess(pid)

	      Wait for child process. Calls Ns_WaitForProcess with NULL statusPtr. Returns NS_OK on success, or NS_ERROR on failure.

       ns_fork()

	      Posix style fork(), using fork1() on Solaris if needed.

SEE ALSO

       nsd(1), info(n)

KEYWORDS

AOLserver								4.0						       Ns_Exec(3aolserver)

Check Out this Related Man Page

FORK(2) 						      BSD System Calls Manual							   FORK(2)

NAME

     fork -- create a new process

SYNOPSIS

     #include <unistd.h>

     pid_t
     fork(void);

DESCRIPTION

     fork() causes creation of a new process.  The new process (child process) is an exact copy of the calling process (parent process) except for
     the following:

	   o   The child process has a unique process ID.

	   o   The child process has a different parent process ID (i.e., the process ID of the parent process).

	   o   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.

	   o   The child processes resource utilizations are set to 0; see setrlimit(2).

RETURN VALUES

     Upon successful completion, fork() returns a value of 0 to the child process and returns the process ID of the child process to the parent
     process.  Otherwise, a value of -1 is returned to the parent process, no child process is created, and the global variable errno is set to
     indicate the error.

ERRORS

     fork() will fail and no child process will be created if:

     [EAGAIN]		The system-imposed limit on the total number of processes under execution would be exceeded.  This limit is configuration-
			dependent.

     [EAGAIN]		The system-imposed limit MAXUPRC (<sys/param.h>) on the total number of processes under execution by a single user would
			be exceeded.

     [ENOMEM]		There is insufficient swap space for the new process.

LEGACY SYNOPSIS

     #include <sys/types.h>
     #include <unistd.h>

     The include file <sys/types.h> is necessary.

SEE ALSO

     execve(2), sigaction(2), wait(2), compat(5)

HISTORY

     A fork() function call appeared in Version 6 AT&T UNIX.

CAVEATS

     There are limits to what you can do in the child process.	To be totally safe you should restrict yourself to only executing async-signal
     safe operations until such time as one of the exec functions is called.  All APIs, including global data symbols, in any framework or library
     should be assumed to be unsafe after a fork() unless explicitly documented to be safe or async-signal safe.  If you need to use these frame-
     works in the child process, you must exec.  In this situation it is reasonable to exec yourself.

4th Berkeley Distribution					   June 4, 1993 					 4th Berkeley Distribution

Linux and UNIX Man Pages

ns_fork(3aolserv) [debian man page]

Check Out this Related Man Page