github.com/hbdrawn/golang@v0.0.0-20141214014649-6b835209aba2/src/syscall/syscall.go (about)

     1  // Copyright 2009 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package syscall contains an interface to the low-level operating system
     6  // primitives.  The details vary depending on the underlying system, and
     7  // by default, godoc will display the syscall documentation for the current
     8  // system.  If you want godoc to display syscall documentation for another
     9  // system, set $GOOS and $GOARCH to the desired system.  For example, if
    10  // you want to view documentation for freebsd/arm on linux/amd64, set $GOOS
    11  // to freebsd and $GOARCH to arm.
    12  // The primary use of syscall is inside other packages that provide a more
    13  // portable interface to the system, such as "os", "time" and "net".  Use
    14  // those packages rather than this one if you can.
    15  // For details of the functions and data types in this package consult
    16  // the manuals for the appropriate operating system.
    17  // These calls return err == nil to indicate success; otherwise
    18  // err is an operating system error describing the failure.
    19  // On most systems, that error has type syscall.Errno.
    20  //
    21  // NOTE: This package is locked down. Code outside the standard
    22  // Go repository should be migrated to use the corresponding
    23  // package in the go.sys subrepository. That is also where updates
    24  // required by new systems or versions should be applied.
    25  // See https://golang.org/s/go1.4-syscall for more information.
    26  //
    27  package syscall
    28  
    29  import "unsafe"
    30  
    31  // StringByteSlice is deprecated. Use ByteSliceFromString instead.
    32  // If s contains a NUL byte this function panics instead of
    33  // returning an error.
    34  func StringByteSlice(s string) []byte {
    35  	a, err := ByteSliceFromString(s)
    36  	if err != nil {
    37  		panic("syscall: string with NUL passed to StringByteSlice")
    38  	}
    39  	return a
    40  }
    41  
    42  // ByteSliceFromString returns a NUL-terminated slice of bytes
    43  // containing the text of s. If s contains a NUL byte at any
    44  // location, it returns (nil, EINVAL).
    45  func ByteSliceFromString(s string) ([]byte, error) {
    46  	for i := 0; i < len(s); i++ {
    47  		if s[i] == 0 {
    48  			return nil, EINVAL
    49  		}
    50  	}
    51  	a := make([]byte, len(s)+1)
    52  	copy(a, s)
    53  	return a, nil
    54  }
    55  
    56  // StringBytePtr is deprecated. Use BytePtrFromString instead.
    57  // If s contains a NUL byte this function panics instead of
    58  // returning an error.
    59  func StringBytePtr(s string) *byte { return &StringByteSlice(s)[0] }
    60  
    61  // BytePtrFromString returns a pointer to a NUL-terminated array of
    62  // bytes containing the text of s. If s contains a NUL byte at any
    63  // location, it returns (nil, EINVAL).
    64  func BytePtrFromString(s string) (*byte, error) {
    65  	a, err := ByteSliceFromString(s)
    66  	if err != nil {
    67  		return nil, err
    68  	}
    69  	return &a[0], nil
    70  }
    71  
    72  // Single-word zero for use when we need a valid pointer to 0 bytes.
    73  // See mksyscall.pl.
    74  var _zero uintptr
    75  
    76  func (ts *Timespec) Unix() (sec int64, nsec int64) {
    77  	return int64(ts.Sec), int64(ts.Nsec)
    78  }
    79  
    80  func (tv *Timeval) Unix() (sec int64, nsec int64) {
    81  	return int64(tv.Sec), int64(tv.Usec) * 1000
    82  }
    83  
    84  func (ts *Timespec) Nano() int64 {
    85  	return int64(ts.Sec)*1e9 + int64(ts.Nsec)
    86  }
    87  
    88  func (tv *Timeval) Nano() int64 {
    89  	return int64(tv.Sec)*1e9 + int64(tv.Usec)*1000
    90  }
    91  
    92  // use is a no-op, but the compiler cannot see that it is.
    93  // Calling use(p) ensures that p is kept live until that point.
    94  //go:noescape
    95  func use(p unsafe.Pointer)