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SYSCALL(2)               DragonFly System Calls Manual              SYSCALL(2)


syscall, __syscall -- indirect system call


Standard C Library (libc, -lc)


#include <sys/syscall.h> #include <unistd.h> int syscall(int number, ...); off_t __syscall(quad_t number, ...);


Syscall() performs the system call whose assembly language interface has the specified number with the specified arguments. Symbolic constants for system calls can be found in the header file <sys/syscall.h>. The __syscall() form should be used when one or more of the parameters is a 64-bit argument to ensure that argument alignment is correct. This sys- tem call is useful for testing new system calls that do not have entries in the C library.


The return values are defined by the system call being invoked. In gen- eral, a 0 return value indicates success. A -1 return value indicates an error, and an error code is stored in errno.


The syscall() function call appeared in 4.0BSD.


There is no way to simulate system calls that have multiple return values such as pipe(2). DragonFly 3.5 June 16, 1993 DragonFly 3.5

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