.

wcfs/internal/wcfs_misc.cpp

@@ -17,14 +17,22 @@
 // See COPYING file for full licensing terms.
 // See https://www.nexedi.com/licensing for rationale and options.
 
+// XXX #define  _GNU_SOURCE ?
+
 #include "wcfs_misc.h"
 
+#include <stdarg.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <memory>
+
 // os::
 namespace os {
 
 tuple<File, error> open(const string &path, int flags, mode_t mode) {
     File f = {._fd = -1, .path = path};
-    int err = std::open(path.c_str(), flags, mode);
+    int err = ::open(path.c_str(), flags, mode);
     if (err != 0)
         return make_tuple(f, f._errno("open"));
 }
@@ -32,7 +40,7 @@ tuple<File, error> open(const string &path, int flags, mode_t mode) {
 error File::close() {
     File *f = this;
 
-    int err = close(f->_fd);
+    int err = ::close(f->_fd);
     if (err != 0)
         return f->_errno("close");
 }
@@ -50,7 +58,9 @@ error File::stat(struct stat *st) {
 // _errno returns error corresponding to op and errno.
 error File::_errno(const char *op) {
     File *f = this;
-    return errorf("%s %s: %s", op, f->path, strerror_r(errno));
+    char ebuf[128];
+    char *estr = strerror_r(errno, ebuf, sizeof(ebuf));
+    return fmt::errorf("%s %s: %s", op, f->_path, estr);
 }
 
 }   // os::
@@ -60,7 +70,7 @@ error File::_errno(const char *op) {
 namespace fmt {
 
 string sprintf(const string &format, ...) {
-    // https://stackoverflow.com/a/26221725/9456786
+    // based on https://stackoverflow.com/a/26221725/9456786
     va_list ap;
 
     va_start(ap, format);
@@ -74,4 +84,10 @@ string sprintf(const string &format, ...) {
     return string(buf.get(), buf.get() + size - 1 ); // without trailing '\0'
 }
 
+error errorf(const string &format, ...) {
+    error err;
+    err.err = fmt::sprintf(format, ...);    // XXX
+    return err;
+}
+
 }   // fmt::

wcfs/internal/wcfs_misc.h

@@ -35,7 +35,7 @@ const nullptr_t nil = nullptr;
 
 // error mimics error from Go.
 struct error {
-    string err;
+    string err;	// XXX -> private + ,error() ?
 
     error()             {}
     error(nullptr_t)    {}          //  = nil
@@ -61,7 +61,7 @@ class File {
     string _path;
 
 public:
-    friend open...
+    friend tuple<File, error> open(const string &path, int flags, mode_t mode);
     // XXX empty ctor -> fd=-1, path=?
     int fd();
     string name();
@@ -85,6 +85,7 @@ tuple<File, error> open(const string &path, int flags = O_RDONLY,
 namespace fmt {
 
 string sprintf(const string &format, ...);
+error  errorf (const string &format, ...);
 
 }   // fmt::