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/*
* This source code is released into the public domain.
*/
module;
#include <cstdint>
#include <expected>
#include <string>
#include <system_error>
#include <vector>
#include <unistd.h>
module nihil.posix;
import nihil.error;
namespace nihil {
auto getenv(std::string_view varname) -> std::expected<std::string, error>
{
// Start with a buffer of this size, and double it every iteration.
constexpr auto bufinc = std::size_t{1024};
auto cvarname = std::string(varname);
auto buf = std::vector<char>(bufinc);
for (;;) {
auto const ret = ::getenv_r(cvarname.c_str(),
buf.data(), buf.size());
if (ret == 0)
return {std::string(buf.data())};
if (ret == -1 && errno == ERANGE) {
buf.resize(buf.size() * 2);
continue;
}
return std::unexpected(error(std::errc(errno)));
}
}
} // namespace nihil
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