module os #include // #include #include 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.ferror(stream &C.FILE) int fn C.feof(stream &C.FILE) int fn C.CopyFile(&u16, &u16, bool) int // fn C.lstat(charptr, voidptr) u64 fn C._wstat64(&char, voidptr) u64 fn C.chown(&char, int, int) int fn C.ftruncate(voidptr, u64) int fn C._chsize_s(voidptr, u64) int // 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) res.trim(nr_read_elements * fsize) return res } // 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, 1, fsize, fp)) is_eof := int(C.feof(fp)) is_error := int(C.ferror(fp)) if is_eof == 0 && is_error != 0 { free(str) return error('fread failed') } str[nelements] = 0 if nelements == 0 { // It is highly likely that the file was a virtual file from // /sys or /proc, with information generated on the fly, so // fsize was not reliably reported. Using vstring() here is // slower (it calls strlen internally), but will return more // consistent results. // For example reading from /sys/class/sound/card0/id produces // a `PCH\n` string, but fsize is 4096, and otherwise you would // get a V string with .len = 4096 and .str = "PCH\n\\000". return str.vstring() } return str.vstring_with_len(nelements) } } // ***************************** OS ops ************************ // // truncate changes the size of the file located in `path` to `len`. // Note that changing symbolic links on Windows only works as admin. pub fn truncate(path string, len u64) ? { fp := C.open(&char(path.str), o_wronly | o_trunc) defer { C.close(fp) } if fp < 0 { return error_with_code(posix_get_error_msg(C.errno), C.errno) } $if windows { if C._chsize_s(fp, len) != 0 { return error_with_code(posix_get_error_msg(C.errno), C.errno) } } $else { if C.ftruncate(fp, len) != 0 { return error_with_code(posix_get_error_msg(C.errno), C.errno) } } } fn eprintln_unknown_file_size() { eprintln('os.file_size() Cannot determine file-size: ' + posix_get_error_msg(C.errno)) } // file_size returns the size of the file located in `path`. // If an error occurs it returns 0. // Note that use of this on symbolic links on Windows returns always 0. pub fn file_size(path string) u64 { mut s := C.stat{} unsafe { $if x64 { $if windows { mut swin := C.__stat64{} if C._wstat64(&char(path.to_wide()), voidptr(&swin)) != 0 { eprintln_unknown_file_size() return 0 } return swin.st_size } $else { if C.stat(&char(path.str), &s) != 0 { eprintln_unknown_file_size() return 0 } 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 { if C._wstat(path.to_wide(), voidptr(&s)) != 0 { eprintln_unknown_file_size() return 0 } return u64(s.st_size) } $else { if C.stat(&char(path.str), &s) != 0 { eprintln_unknown_file_size() return 0 } 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)) } // TODO use defer{} to close files in case of error or return. // Currently there is a C-Error when building. mut buf := [1024]byte{} mut count := 0 for { count = C.read(fp_from, &buf[0], sizeof(buf)) if count == 0 { break } if C.write(fp_to, &buf[0], count) < 0 { C.close(fp_to) C.close(fp_from) 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 { C.close(fp_to) C.close(fp_from) 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, c'/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) ? { $if windows { rc := C.RemoveDirectory(&char(path.to_wide())) if rc == 0 { // https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-removedirectorya - 0 is failure return error('Failed to remove "$path": ' + posix_get_error_msg(C.errno)) } } $else { rc := C.rmdir(&char(path.str)) if rc == -1 { return error(posix_get_error_msg(C.errno)) } } } // print_c_errno will print the current value of `C.errno`. fn print_c_errno() { e := C.errno se := unsafe { tos_clone(&byte(C.strerror(e))) } println('errno=$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 := u32(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), int(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(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) } nread := C.fread(buf, tsize, len, fp) C.fclose(fp) return unsafe { array{ element_size: tsize data: buf len: int(nread) cap: len } } } pub fn on_segfault(f voidptr) { $if windows { return } $if macos { C.printf(c'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() } return unsafe { xresult.vstring() } } $if windows { max := 512 size := max * 2 // max_path_len * sizeof(wchar_t) mut result := unsafe { &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 := unsafe { &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 { path_ := path.replace('/', '\\') attr := C.GetFileAttributesW(path_.to_wide()) return int(attr) != int(C.INVALID_FILE_ATTRIBUTES) && (attr & 0x400) != 0 } $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(max_path_len) unsafe { if C.getcwd(&char(buf), max_path_len) == 0 { free(buf) return '' } return buf.vstring() } } } // 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) mut res := '' $if windows { // GetFullPathName doesn't work with symbolic links, // so if it is not a file, get full path 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 { unsafe { free(fullpath) } return fpath.clone() } res = unsafe { string_from_wide(fullpath) } } $else { fullpath = vcalloc(max_path_len) ret := &char(C.realpath(&char(fpath.str), &char(fullpath))) if ret == 0 { unsafe { free(fullpath) } return fpath.clone() } res = unsafe { fullpath.vstring() } } return normalize_drive_letter(res) } [direct_array_access; manualfree] 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 } // 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) { if C.chmod(&char(path.str), mode) != 0 { panic('chmod failed: ' + posix_get_error_msg(C.errno)) } } // chown changes the owner and group attributes of `path` to `owner` and `group`. pub fn chown(path string, owner int, group int) ? { $if windows { return error('os.chown() not implemented for Windows') } $else { if C.chown(&char(path.str), owner, group) != 0 { return error_with_code(posix_get_error_msg(C.errno), C.errno) } } } // 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) } }