| // Copyright 2020 The Abseil Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // https://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #include "absl/base/internal/strerror.h" |
| |
| #include <cerrno> |
| #include <cstddef> |
| #include <cstdio> |
| #include <cstring> |
| #include <string> |
| #include <type_traits> |
| |
| #include "absl/base/attributes.h" |
| #include "absl/base/internal/errno_saver.h" |
| |
| namespace absl { |
| ABSL_NAMESPACE_BEGIN |
| namespace base_internal { |
| namespace { |
| const char* StrErrorAdaptor(int errnum, char* buf, size_t buflen) { |
| #if defined(_WIN32) |
| int rc = strerror_s(buf, buflen, errnum); |
| buf[buflen - 1] = '\0'; // guarantee NUL termination |
| if (rc == 0 && strncmp(buf, "Unknown error", buflen) == 0) *buf = '\0'; |
| return buf; |
| #else |
| #if defined(__GLIBC__) || defined(__APPLE__) |
| // Use the BSD sys_errlist API provided by GNU glibc and others to |
| // avoid any need to copy the message into the local buffer first. |
| if (0 <= errnum && errnum < sys_nerr) { |
| if (const char* p = sys_errlist[errnum]) { |
| return p; |
| } |
| } |
| #endif |
| // The type of `ret` is platform-specific; both of these branches must compile |
| // either way but only one will execute on any given platform: |
| auto ret = strerror_r(errnum, buf, buflen); |
| if (std::is_same<decltype(ret), int>::value) { |
| // XSI `strerror_r`; `ret` is `int`: |
| if (ret) *buf = '\0'; |
| return buf; |
| } else { |
| // GNU `strerror_r`; `ret` is `char *`: |
| return reinterpret_cast<const char*>(ret); |
| } |
| #endif |
| } |
| } // namespace |
| |
| std::string StrError(int errnum) { |
| absl::base_internal::ErrnoSaver errno_saver; |
| char buf[100]; |
| const char* str = StrErrorAdaptor(errnum, buf, sizeof buf); |
| if (*str == '\0') { |
| snprintf(buf, sizeof buf, "Unknown error %d", errnum); |
| str = buf; |
| } |
| return str; |
| } |
| |
| } // namespace base_internal |
| ABSL_NAMESPACE_END |
| } // namespace absl |