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).

Note:

We provide this function for backward compatibility. Don't use it; use posix_spawn() instead.
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 ioctl() commands are allowed, and input attempts result in an EOF indication.
Don't call vfork() from a multithreaded process.

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:

Standard Unix; removed from POSIX.1-2008

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