syscall(2) [bsd man page]

SYSCALL(2)							System Calls Manual							SYSCALL(2)

NAME

       syscall - indirect system call

SYNOPSIS

       #include <syscall.h>

       syscall(number, arg, ...)  (VAX-11)

DESCRIPTION

       Syscall performs the system call whose assembly language interface has the specified number, register arguments r0 and r1 and further argu-
       ments arg.  Symbolic constants for system calls can be found in the header file <syscall.h>.

       The r0 value of the system call is returned.

DIAGNOSTICS

       When the C-bit is set, syscall returns -1 and sets the external variable errno (see intro(2)).

BUGS

       There is no way to simulate system calls such as pipe(2), which return values in register r1.

4th Berkeley Distribution					  April 16, 1986							SYSCALL(2)

syscall(3UCB)					     SunOS/BSD Compatibility Library Functions					     syscall(3UCB)

NAME

       syscall - indirect system call

SYNOPSIS

       /usr/ucb/cc [ flag ... ] file ...
       #include <sys/syscall.h>

       int syscall(number,  arg,  ...);

DESCRIPTION

       syscall()  performs the function whose assembly language interface has the specified number, and arguments arg ....  Symbolic constants for
       functions can be found in the header <sys/syscall.h>.

RETURN VALUES

       On error syscall() returns -1 and sets the external variable errno (see intro(2)).

FILES

       <sys/syscall.h>

SEE ALSO

       intro(2), pipe(2)

NOTES

       Use of these interfaces should be restricted to only applications written on BSD platforms.  Use of these interfaces with any of the system
       libraries or in multi-thread applications is unsupported.

WARNINGS

       There is no way to use syscall() to call functions such as pipe(2) which return values that do not fit into one hardware register.

       Since  many  system  calls  are	implemented  as library wrappers around traps to the kernel, these calls may not behave as documented when
       called from syscall(), which bypasses these wrappers. For these reasons, using syscall() is not recommended.

SunOS 5.10							    22 Jan 1993 						     syscall(3UCB)