TH SYSCALL 1
SH NAME
syscall \- test a system call
SH SYNOPSIS
B syscall
[
B -osx
]
I entry
[
I arg ...
]
SH DESCRIPTION
I Syscall
invokes the system call
I entry
with the given arguments.
(Some functions, such as
I write
and
IR read (2),
although not strictly system calls, are valid
IR entries .)
It prints the return value and the error string, if there was an error.
An argument is either an integer constant as in C (its value is passed),
a string (its address is passed),
or the literal
B buf
(a pointer to a 1 Kbyte buffer is passed).
PP
If
B -o
is given, the contents of the 1 Kbyte buffer are printed as a zero-terminated string
after the system call is done.
The
B -x
and
B -s
options are similar, but
B -x
formats the data as hexadecimal bytes, while
B -s
interprets the data as a
IR stat (5)
message and formats it similar to the style of
B ls
B -lqm
(see
IR ls (1)),
with extra detail about the modify and access times.
SH EXAMPLES
Write a string to standard output:
IP
EX
syscall write 1 hello 5
EE
PP
Print information about the file connected to standard input:
IP
EX
syscall -s fstat 0 buf 1024
EE
SH SOURCE
B /sys/src/cmd/syscall
SH "SEE ALSO"
Section 2 of this manual.
SH DIAGNOSTICS
If
I entry
is not known to
IR syscall ,
the exit status is
LR unknown .
If the system call succeeds, the exit status is null;
otherwise the exit status is the string that
IR errstr (2)
returns.
