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vfork()

Spawn a new process and block the parent

Synopsis:

#include <process.h>

pid_t  vfork( void );

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

This function spawns a new process and blocks the parent until the child process calls execve() or exits (by calling _exit() or abnormally).

Returns:

A value of zero to the child process, and (later) the child's process ID in the parent. If an error occurs, no child process is created, and the function returns -1 and sets errno.

Errors:

EAGAIN

The system-imposed limit on the total number of processes under execution would be exceeded. This limit is determined when the system is generated.

ENOMEM

There isn't enough memory for the new process.

Classification:

POSIX 1003.1 XSI

Safety:
Cancellation point	No
Interrupt handler	No
Signal handler	No
Thread	No

Caveats:

To avoid a possible deadlock situation, processes that are children in the middle of a vfork() are never sent SIGTTOU or SIGTTIN signals; rather, output or ioctls are allowed and input attempts result in an EOF indication.

See also:

execve(), _exit(), fork(), ioctl(), sigaction(), wait()

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