v/vlib/os/os_c.v

893 lines
22 KiB
V

module os
#include <sys/stat.h> // #include <signal.h>
#include <errno.h>
struct C.dirent {
d_name [256]char
}
fn C.readdir(voidptr) &C.dirent
fn C.readlink(pathname &char, buf &char, bufsiz size_t) int
fn C.getline(voidptr, voidptr, voidptr) int
fn C.ftell(fp voidptr) int
fn C.sigaction(int, voidptr, int) int
fn C.open(&char, int, ...int) int
fn C.fdopen(fd int, mode &char) &C.FILE
fn C.CopyFile(&u32, &u32, int) int
// fn C.lstat(charptr, voidptr) u64
fn C._wstat64(&char, voidptr) u64
// fn C.proc_pidpath(int, byteptr, int) int
struct C.stat {
st_size u64
st_mode u32
st_mtime int
}
struct C.__stat64 {
st_size u64
st_mode u32
st_mtime int
}
struct C.DIR {
}
type FN_SA_Handler = fn (sig int)
struct C.sigaction {
mut:
sa_mask int
sa_sigaction int
sa_flags int
sa_handler FN_SA_Handler
}
struct C.dirent {
d_name &byte
}
// read_bytes returns all bytes read from file in `path`.
[manualfree]
pub fn read_bytes(path string) ?[]byte {
mut fp := vfopen(path, 'rb') ?
cseek := C.fseek(fp, 0, C.SEEK_END)
if cseek != 0 {
return error('fseek failed')
}
fsize := C.ftell(fp)
if fsize < 0 {
return error('ftell failed')
}
C.rewind(fp)
mut res := []byte{len: fsize}
nr_read_elements := int(C.fread(res.data, fsize, 1, fp))
if nr_read_elements == 0 && fsize > 0 {
return error('fread failed')
}
C.fclose(fp)
fres := res[0..nr_read_elements * fsize].clone()
unsafe { res.free() }
return fres
}
// read_file reads the file in `path` and returns the contents.
pub fn read_file(path string) ?string {
mode := 'rb'
mut fp := vfopen(path, mode) ?
defer {
C.fclose(fp)
}
cseek := C.fseek(fp, 0, C.SEEK_END)
if cseek != 0 {
return error('fseek failed')
}
fsize := C.ftell(fp)
if fsize < 0 {
return error('ftell failed')
}
// C.fseek(fp, 0, SEEK_SET) // same as `C.rewind(fp)` below
C.rewind(fp)
unsafe {
mut str := malloc(fsize + 1)
nelements := int(C.fread(str, fsize, 1, fp))
if nelements == 0 && fsize > 0 {
free(str)
return error('fread failed')
}
str[fsize] = 0
return str.vstring_with_len(fsize)
}
}
// ***************************** OS ops ************************
// file_size returns the size of the file located in `path`.
pub fn file_size(path string) u64 {
mut s := C.stat{}
unsafe {
$if x64 {
$if windows {
mut swin := C.__stat64{}
C._wstat64(path.to_wide(), voidptr(&swin))
return swin.st_size
} $else {
C.stat(&char(path.str), &s)
return u64(s.st_size)
}
}
$if x32 {
$if debug {
println('Using os.file_size() on 32bit systems may not work on big files.')
}
$if windows {
C._wstat(path.to_wide(), voidptr(&s))
return u64(s.st_size)
} $else {
C.stat(&char(path.str), &s)
return u64(s.st_size)
}
}
}
return 0
}
// mv moves files or folders from `src` to `dst`.
pub fn mv(src string, dst string) ? {
mut rdst := dst
if is_dir(rdst) {
rdst = join_path(rdst.trim_right(path_separator), file_name(src.trim_right(path_separator)))
}
$if windows {
w_src := src.replace('/', '\\')
w_dst := rdst.replace('/', '\\')
ret := C._wrename(w_src.to_wide(), w_dst.to_wide())
if ret != 0 {
return error_with_code('failed to rename $src to $dst', int(ret))
}
} $else {
ret := C.rename(&char(src.str), &char(rdst.str))
if ret != 0 {
return error_with_code('failed to rename $src to $dst', int(ret))
}
}
}
// cp copies files or folders from `src` to `dst`.
pub fn cp(src string, dst string) ? {
$if windows {
w_src := src.replace('/', '\\')
w_dst := dst.replace('/', '\\')
if C.CopyFile(w_src.to_wide(), w_dst.to_wide(), false) == 0 {
result := C.GetLastError()
return error_with_code('failed to copy $src to $dst', int(result))
}
} $else {
fp_from := C.open(&char(src.str), C.O_RDONLY)
if fp_from < 0 { // Check if file opened
return error_with_code('cp: failed to open $src', int(fp_from))
}
fp_to := C.open(&char(dst.str), C.O_WRONLY | C.O_CREAT | C.O_TRUNC, C.S_IWUSR | C.S_IRUSR)
if fp_to < 0 { // Check if file opened (permissions problems ...)
C.close(fp_from)
return error_with_code('cp (permission): failed to write to $dst (fp_to: $fp_to)',
int(fp_to))
}
mut buf := [1024]byte{}
mut count := 0
for {
// FIXME: use sizeof, bug: 'os__buf' undeclared
// count = C.read(fp_from, buf, sizeof(buf))
count = C.read(fp_from, &buf[0], 1024)
if count == 0 {
break
}
if C.write(fp_to, &buf[0], count) < 0 {
return error_with_code('cp: failed to write to $dst', int(-1))
}
}
from_attr := C.stat{}
unsafe {
C.stat(&char(src.str), &from_attr)
}
if C.chmod(&char(dst.str), from_attr.st_mode) < 0 {
return error_with_code('failed to set permissions for $dst', int(-1))
}
C.close(fp_to)
C.close(fp_from)
}
}
// vfopen returns an opened C file, given its path and open mode.
// NB: os.vfopen is useful for compatibility with C libraries, that expect `FILE *`.
// If you write pure V code, os.create or os.open are more convenient.
pub fn vfopen(path string, mode string) ?&C.FILE {
if path.len == 0 {
return error('vfopen called with ""')
}
mut fp := voidptr(0)
$if windows {
fp = C._wfopen(path.to_wide(), mode.to_wide())
} $else {
fp = C.fopen(&char(path.str), &char(mode.str))
}
if isnil(fp) {
return error('failed to open file "$path"')
} else {
return fp
}
}
// fileno returns the file descriptor of an opened C file.
pub fn fileno(cfile voidptr) int {
$if windows {
return C._fileno(cfile)
} $else {
mut cfile_casted := &C.FILE(0) // FILE* cfile_casted = 0;
cfile_casted = cfile
// Required on FreeBSD/OpenBSD/NetBSD as stdio.h defines fileno(..) with a macro
// that performs a field access on its argument without casting from void*.
return C.fileno(cfile_casted)
}
}
// vpopen system starts the specified command, waits for it to complete, and returns its code.
fn vpopen(path string) voidptr {
// *C.FILE {
$if windows {
mode := 'rb'
wpath := path.to_wide()
return C._wpopen(wpath, mode.to_wide())
} $else {
cpath := path.str
return C.popen(&char(cpath), c'r')
}
}
fn posix_wait4_to_exit_status(waitret int) (int, bool) {
$if windows {
return waitret, false
} $else {
mut ret := 0
mut is_signaled := true
// (see man system, man 2 waitpid: C macro WEXITSTATUS section)
if C.WIFEXITED(waitret) {
ret = C.WEXITSTATUS(waitret)
is_signaled = false
} else if C.WIFSIGNALED(waitret) {
ret = C.WTERMSIG(waitret)
is_signaled = true
}
return ret, is_signaled
}
}
// posix_get_error_msg return error code representation in string.
pub fn posix_get_error_msg(code int) string {
ptr_text := C.strerror(code) // voidptr?
if ptr_text == 0 {
return ''
}
return unsafe { tos3(ptr_text) }
}
// vpclose will close a file pointer opened with `vpopen`.
fn vpclose(f voidptr) int {
$if windows {
return C._pclose(f)
} $else {
ret, _ := posix_wait4_to_exit_status(C.pclose(f))
return ret
}
}
// system works like `exec`, but only returns a return code.
pub fn system(cmd string) int {
// if cmd.contains(';') || cmd.contains('&&') || cmd.contains('||') || cmd.contains('\n') {
// TODO remove panic
// panic(';, &&, || and \\n are not allowed in shell commands')
// }
mut ret := 0
$if windows {
// overcome bug in system & _wsystem (cmd) when first char is quote `"`
wcmd := if cmd.len > 1 && cmd[0] == `"` && cmd[1] != `"` { '"$cmd"' } else { cmd }
unsafe {
ret = C._wsystem(wcmd.to_wide())
}
} $else {
$if ios {
unsafe {
arg := [c'/bin/sh', c'-c', &byte(cmd.str), 0]
pid := 0
ret = C.posix_spawn(&pid, '/bin/sh', 0, 0, arg.data, 0)
status := 0
ret = C.waitpid(pid, &status, 0)
if C.WIFEXITED(status) {
ret = C.WEXITSTATUS(status)
}
}
} $else {
unsafe {
ret = C.system(&char(cmd.str))
}
}
}
if ret == -1 {
print_c_errno()
}
$if !windows {
pret, is_signaled := posix_wait4_to_exit_status(ret)
if is_signaled {
println('Terminated by signal ${ret:2d} (' + sigint_to_signal_name(pret) + ')')
}
ret = pret
}
return ret
}
// exists returns true if `path` (file or directory) exists.
pub fn exists(path string) bool {
$if windows {
p := path.replace('/', '\\')
return C._waccess(p.to_wide(), f_ok) != -1
} $else {
return C.access(&char(path.str), f_ok) != -1
}
}
// is_executable returns `true` if `path` is executable.
pub fn is_executable(path string) bool {
$if windows {
// NB: https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/access-waccess?view=vs-2019
// i.e. there is no X bit there, the modes can be:
// 00 Existence only
// 02 Write-only
// 04 Read-only
// 06 Read and write
p := real_path(path)
return (exists(p) && p.ends_with('.exe'))
}
$if solaris {
statbuf := C.stat{}
unsafe {
if C.stat(&char(path.str), &statbuf) != 0 {
return false
}
}
return (int(statbuf.st_mode) & (s_ixusr | s_ixgrp | s_ixoth)) != 0
}
return C.access(&char(path.str), x_ok) != -1
}
// is_writable returns `true` if `path` is writable.
pub fn is_writable(path string) bool {
$if windows {
p := path.replace('/', '\\')
return C._waccess(p.to_wide(), w_ok) != -1
} $else {
return C.access(&char(path.str), w_ok) != -1
}
}
// is_readable returns `true` if `path` is readable.
pub fn is_readable(path string) bool {
$if windows {
p := path.replace('/', '\\')
return C._waccess(p.to_wide(), r_ok) != -1
} $else {
return C.access(&char(path.str), r_ok) != -1
}
}
// rm removes file in `path`.
pub fn rm(path string) ? {
mut rc := 0
$if windows {
rc = C._wremove(path.to_wide())
} $else {
rc = C.remove(&char(path.str))
}
if rc == -1 {
return error('Failed to remove "$path": ' + posix_get_error_msg(C.errno))
}
// C.unlink(path.cstr())
}
// rmdir removes a specified directory.
pub fn rmdir(path string) ? {
$if windows {
rc := C.RemoveDirectory(path.to_wide())
if rc == 0 {
// https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-removedirectorya - 0 is failure
return error('Failed to remove "$path": ' + posix_get_error_msg(C.errno))
}
} $else {
rc := C.rmdir(&char(path.str))
if rc == -1 {
return error(posix_get_error_msg(C.errno))
}
}
}
// print_c_errno will print the current value of `C.errno`.
fn print_c_errno() {
e := C.errno
se := unsafe { tos_clone(&byte(C.strerror(C.errno))) }
println('errno=$e err=$se')
}
// get_raw_line returns a one-line string from stdin along with '\n' if there is any.
pub fn get_raw_line() string {
$if windows {
unsafe {
max_line_chars := 256
buf := malloc(max_line_chars * 2)
h_input := C.GetStdHandle(C.STD_INPUT_HANDLE)
mut bytes_read := 0
if is_atty(0) > 0 {
x := C.ReadConsole(h_input, buf, max_line_chars * 2, &bytes_read, 0)
if !x {
return tos(buf, 0)
}
return string_from_wide2(&u16(buf), bytes_read)
}
mut offset := 0
for {
pos := buf + offset
res := C.ReadFile(h_input, pos, 1, C.LPDWORD(&bytes_read), 0)
if !res && offset == 0 {
return tos(buf, 0)
}
if !res || bytes_read == 0 {
break
}
if *pos == `\n` || *pos == `\r` {
offset++
break
}
offset++
}
return buf.vstring_with_len(offset)
}
} $else {
max := size_t(0)
buf := &char(0)
nr_chars := unsafe { C.getline(&buf, &max, C.stdin) }
return unsafe { tos(&byte(buf), if nr_chars < 0 { 0 } else { nr_chars }) }
}
}
// get_raw_stdin will get the raw input from stdin.
pub fn get_raw_stdin() []byte {
$if windows {
unsafe {
block_bytes := 512
mut old_size := block_bytes
mut buf := malloc(block_bytes)
h_input := C.GetStdHandle(C.STD_INPUT_HANDLE)
mut bytes_read := 0
mut offset := 0
for {
pos := buf + offset
res := C.ReadFile(h_input, pos, block_bytes, C.LPDWORD(&bytes_read), 0)
offset += bytes_read
if !res {
break
}
new_size := offset + block_bytes + (block_bytes - bytes_read)
buf = realloc_data(buf, old_size, new_size)
old_size = new_size
}
return array{
element_size: 1
data: voidptr(buf)
len: offset
cap: offset
}
}
} $else {
max := size_t(0)
buf := &char(0)
nr_chars := unsafe { C.getline(&buf, &max, C.stdin) }
return array{
element_size: 1
data: voidptr(buf)
len: if nr_chars < 0 { 0 } else { nr_chars }
cap: int(max)
}
}
}
// read_file_array reads an array of `T` values from file `path`.
pub fn read_file_array<T>(path string) []T {
a := T{}
tsize := int(sizeof(a))
// prepare for reading, get current file size
mut fp := vfopen(path, 'rb') or { return []T{} }
C.fseek(fp, 0, C.SEEK_END)
fsize := C.ftell(fp)
C.rewind(fp)
// read the actual data from the file
len := fsize / tsize
buf := unsafe { malloc(fsize) }
C.fread(buf, fsize, 1, fp)
C.fclose(fp)
return unsafe {
array{
element_size: tsize
data: buf
len: len
cap: len
}
}
}
pub fn on_segfault(f voidptr) {
$if windows {
return
}
$if macos {
C.printf('TODO')
/*
mut sa := C.sigaction{}
C.memset(&sa, 0, sizeof(C.sigaction_size))
C.sigemptyset(&sa.sa_mask)
sa.sa_sigaction = f
sa.sa_flags = C.SA_SIGINFO
C.sigaction(C.SIGSEGV, &sa, 0)
*/
}
}
// executable returns the path name of the executable that started the current
// process.
[manualfree]
pub fn executable() string {
$if linux {
mut xresult := vcalloc(max_path_len)
count := C.readlink(c'/proc/self/exe', &char(xresult), max_path_len)
if count < 0 {
eprintln('os.executable() failed at reading /proc/self/exe to get exe path')
return executable_fallback()
}
res := unsafe { xresult.vstring() }.clone()
unsafe { free(xresult) }
return res
}
$if windows {
max := 512
size := max * 2 // max_path_len * sizeof(wchar_t)
mut result := &u16(vcalloc(size))
len := C.GetModuleFileName(0, result, max)
// determine if the file is a windows symlink
attrs := C.GetFileAttributesW(result)
is_set := attrs & 0x400 // FILE_ATTRIBUTE_REPARSE_POINT
if is_set != 0 { // it's a windows symlink
// gets handle with GENERIC_READ, FILE_SHARE_READ, 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0
file := C.CreateFile(result, 0x80000000, 1, 0, 3, 0x80, 0)
if file != voidptr(-1) {
final_path := &u16(vcalloc(size))
// https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-getfinalpathnamebyhandlew
final_len := C.GetFinalPathNameByHandleW(file, final_path, size, 0)
if final_len < size {
ret := unsafe { string_from_wide2(final_path, final_len) }
// remove '\\?\' from beginning (see link above)
return ret[4..]
} else {
eprintln('os.executable() saw that the executable file path was too long')
}
}
C.CloseHandle(file)
}
return unsafe { string_from_wide2(result, len) }
}
$if macos {
mut result := vcalloc(max_path_len)
pid := C.getpid()
ret := proc_pidpath(pid, result, max_path_len)
if ret <= 0 {
eprintln('os.executable() failed at calling proc_pidpath with pid: $pid . proc_pidpath returned $ret ')
return executable_fallback()
}
return unsafe { result.vstring() }
}
$if freebsd {
mut result := vcalloc(max_path_len)
mib := [1 /* CTL_KERN */, 14 /* KERN_PROC */, 12 /* KERN_PROC_PATHNAME */, -1]
size := max_path_len
unsafe { C.sysctl(mib.data, 4, result, &size, 0, 0) }
return unsafe { result.vstring() }
}
// "Sadly there is no way to get the full path of the executed file in OpenBSD."
$if openbsd {
}
$if solaris {
}
$if haiku {
}
$if netbsd {
mut result := vcalloc(max_path_len)
count := C.readlink(c'/proc/curproc/exe', &char(result), max_path_len)
if count < 0 {
eprintln('os.executable() failed at reading /proc/curproc/exe to get exe path')
return executable_fallback()
}
return unsafe { result.vstring_with_len(count) }
}
$if dragonfly {
mut result := vcalloc(max_path_len)
count := C.readlink(c'/proc/curproc/file', &char(result), max_path_len)
if count < 0 {
eprintln('os.executable() failed at reading /proc/curproc/file to get exe path')
return executable_fallback()
}
return unsafe { result.vstring_with_len(count) }
}
return executable_fallback()
}
// is_dir returns a `bool` indicating whether the given `path` is a directory.
pub fn is_dir(path string) bool {
$if windows {
w_path := path.replace('/', '\\')
attr := C.GetFileAttributesW(w_path.to_wide())
if attr == u32(C.INVALID_FILE_ATTRIBUTES) {
return false
}
if int(attr) & C.FILE_ATTRIBUTE_DIRECTORY != 0 {
return true
}
return false
} $else {
statbuf := C.stat{}
if unsafe { C.stat(&char(path.str), &statbuf) } != 0 {
return false
}
// ref: https://code.woboq.org/gcc/include/sys/stat.h.html
val := int(statbuf.st_mode) & s_ifmt
return val == s_ifdir
}
}
// is_link returns a boolean indicating whether `path` is a link.
pub fn is_link(path string) bool {
$if windows {
return false // TODO
} $else {
statbuf := C.stat{}
if C.lstat(&char(path.str), &statbuf) != 0 {
return false
}
return int(statbuf.st_mode) & s_ifmt == s_iflnk
}
}
// chdir changes the current working directory to the new directory in `path`.
pub fn chdir(path string) {
$if windows {
C._wchdir(path.to_wide())
} $else {
C.chdir(&char(path.str))
}
}
// getwd returns the absolute path of the current directory.
pub fn getwd() string {
$if windows {
max := 512 // max_path_len * sizeof(wchar_t)
unsafe {
buf := &u16(vcalloc(max * 2))
if C._wgetcwd(buf, max) == 0 {
free(buf)
return ''
}
return string_from_wide(buf)
}
} $else {
buf := vcalloc(512)
unsafe {
if C.getcwd(&char(buf), 512) == 0 {
free(buf)
return ''
}
res := buf.vstring().clone()
free(buf)
return res
}
}
}
// real_path returns the full absolute path for fpath, with all relative ../../, symlinks and so on resolved.
// See http://pubs.opengroup.org/onlinepubs/9699919799/functions/realpath.html
// Also https://insanecoding.blogspot.com/2007/11/pathmax-simply-isnt.html
// and https://insanecoding.blogspot.com/2007/11/implementing-realpath-in-c.html
// NB: this particular rabbit hole is *deep* ...
[manualfree]
pub fn real_path(fpath string) string {
mut fullpath := &byte(0)
defer {
unsafe { free(fullpath) }
}
$if windows {
fullpath = unsafe { &u16(vcalloc(max_path_len * 2)) }
// TODO: check errors if path len is not enough
ret := C.GetFullPathName(fpath.to_wide(), max_path_len, fullpath, 0)
if ret == 0 {
return fpath
}
} $else {
fullpath = vcalloc(max_path_len)
ret := &char(C.realpath(&char(fpath.str), &char(fullpath)))
if ret == 0 {
return fpath
}
}
mut res := ''
$if windows {
res = unsafe { string_from_wide(fullpath) }
} $else {
res = unsafe { fullpath.vstring() }
}
nres := normalize_drive_letter(res)
cres := nres.clone()
return cres
}
fn normalize_drive_letter(path string) string {
// normalize_drive_letter is needed, because a path like c:\nv\.bin (note the small `c`)
// in %PATH is NOT recognized by cmd.exe (and probably other programs too)...
// Capital drive letters do work fine.
$if !windows {
return path
}
if path.len > 2 && path[0] >= `a` && path[0] <= `z` && path[1] == `:`
&& path[2] == path_separator[0] {
unsafe {
x := &path.str[0]
(*x) = *x - 32
}
}
return path
}
// signal will assign `handler` callback to be called when `signum` signal is received.
pub fn signal(signum int, handler voidptr) voidptr {
res := unsafe { C.signal(signum, handler) }
return res
}
// fork will fork the current system process and return the pid of the fork.
pub fn fork() int {
mut pid := -1
$if !windows {
pid = C.fork()
}
$if windows {
panic('os.fork not supported in windows') // TODO
}
return pid
}
// wait blocks the calling process until one of its child processes exits or a signal is received.
// After child process terminates, parent continues its execution after wait system call instruction.
pub fn wait() int {
mut pid := -1
$if !windows {
pid = C.wait(0)
}
$if windows {
panic('os.wait not supported in windows') // TODO
}
return pid
}
// file_last_mod_unix returns the "last modified" time stamp of file in `path`.
pub fn file_last_mod_unix(path string) int {
attr := C.stat{}
// # struct stat attr;
unsafe { C.stat(&char(path.str), &attr) }
// # stat(path.str, &attr);
return attr.st_mtime
// # return attr.st_mtime ;
}
// flush will flush the stdout buffer.
pub fn flush() {
C.fflush(C.stdout)
}
// chmod change file access attributes of `path` to `mode`.
// Octals like `0o600` can be used.
pub fn chmod(path string, mode int) {
C.chmod(&char(path.str), mode)
}
// open_append opens `path` file for appending.
pub fn open_append(path string) ?File {
mut file := File{}
$if windows {
wpath := path.replace('/', '\\').to_wide()
mode := 'ab'
file = File{
cfile: C._wfopen(wpath, mode.to_wide())
}
} $else {
cpath := path.str
file = File{
cfile: C.fopen(&char(cpath), c'ab')
}
}
if isnil(file.cfile) {
return error('failed to create(append) file "$path"')
}
file.is_opened = true
return file
}
// execvp - loads and executes a new child process, *in place* of the current process.
// The child process executable is located in `cmdpath`.
// The arguments, that will be passed to it are in `args`.
// NB: this function will NOT return when successfull, since
// the child process will take control over execution.
pub fn execvp(cmdpath string, args []string) ? {
mut cargs := []&char{}
cargs << &char(cmdpath.str)
for i in 0 .. args.len {
cargs << &char(args[i].str)
}
cargs << &char(0)
mut res := int(0)
$if windows {
res = C._execvp(&char(cmdpath.str), cargs.data)
} $else {
res = C.execvp(&char(cmdpath.str), cargs.data)
}
if res == -1 {
return error_with_code(posix_get_error_msg(C.errno), C.errno)
}
// just in case C._execvp returned ... that happens on windows ...
exit(res)
}
// execve - loads and executes a new child process, *in place* of the current process.
// The child process executable is located in `cmdpath`.
// The arguments, that will be passed to it are in `args`.
// You can pass environment variables to through `envs`.
// NB: this function will NOT return when successfull, since
// the child process will take control over execution.
pub fn execve(cmdpath string, args []string, envs []string) ? {
mut cargv := []&char{}
mut cenvs := []&char{}
cargv << &char(cmdpath.str)
for i in 0 .. args.len {
cargv << &char(args[i].str)
}
for i in 0 .. envs.len {
cenvs << &char(envs[i].str)
}
cargv << &char(0)
cenvs << &char(0)
mut res := int(0)
$if windows {
res = C._execve(&char(cmdpath.str), cargv.data, cenvs.data)
} $else {
res = C.execve(&char(cmdpath.str), cargv.data, cenvs.data)
}
// NB: normally execve does not return at all.
// If it returns, then something went wrong...
if res == -1 {
return error_with_code(posix_get_error_msg(C.errno), C.errno)
}
}